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AB INITIO BASED MODELING OF

ADVANCED MATERIALS

AMM-2016

Satellite Conference of XX Mendeleev Congress on general

and applied chemistry

Ekaterinburg

22 – 24 September, 2016

–2–

Organizers

Institute of Quantum Institute of Metal Physics

Materials Science CJSC Ural Branch RAS

Ural Hi-Tech Park Ural Federal University

Chairmans

Yuri Gornostyrev (Ekaterinburg, Russia)

Mikhail Katsnelson (Nijmegen, Netherlands)

The conference brings together prominent scientists from the area of theoretical modelling to

assess the state of the art in applications of the electronic structure theory for the knowledge-

based design of advanced materials. Particularly the conference will focus on the development

of theoretical approaches and physical principles of accelerated materials design, discussion of

novel trends in materials science and promote direct interaction between theory and experiment.

The aim is to provide a distinguished atmosphere and framework for exchanging the newest

ideas and concepts in order to resolve the present challenges in the field.

Master class by Alexander I. Poteryaev the “Application of the AMULET code for DFT+DMFT

calculations of realistic compounds” will be held during the conference.

This conference is supported and financed by

ART, SCIENCE AND SPORT CHARITY

FOUNDATION

SVERDLOVSK REGION ADMINISTRATION

RTC AUSFERR

ISBN - 978-5-7691-2455-6

URAL BRANCH RAS

http://www.google.ru/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=0ahUKEwj0x8_Oh9rOAhWEkSwKHQ4IB4oQjRwIBw&url=http://www.artscienceandsport.com/&psig=AFQjCNF00ikcEUMl-AJtt4UyGIl9fSLrgw&ust=1472128318127577

http://www.uran.ru/

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AMM-2016 conference program

22 September

9:30 –10:30 Registration. Coffee is served

10:30 –10:45 Opening. Welcome talk

SESSION 1: DMFT AND ALL THAT

10:45–12:40 Chair Mikhail Katsnelson

10:45 –11:25 Alexander Lichtenstein, University Hamburg, Hamburg, Germany

Strong Electronic Correlations in magnetic materials

11:25 –11:50 Andrey Katanin, IMP Ural Branch RAS, Ural Federal University,

Ekaterinburg, Russia

Non-local effects in strongly-correlated systems

11:50 –12:15 Ivan Leonov, University of Augsburg, Augsburg, Germany

Electronic structure and phase stability of correlated electron materials under

extreme conditions

12:15 –12:40 Sergey Streltsov, Igor Mazin, IMP Ural Branch RAS, Russia, NRL, USA

Molecular orbitals in hexagonal ruthenates

13:00 –14:00 Lunch

14:00-16:10 Chair Tamio Oguchi

14:00 –14:40 Vladimir Anisimov, IMP Ural Branch RAS, Ekaterinburg, Russia

Magnetic and structural properties of iron and its alloys in LDA+DMFT

14:40 –15:20 Olle Eriksson, Uppsala university, Uppsala, Sweden

Theory of x-ray and photoelectron spectroscopy with DMFT

15:20 –15:45 Leonid Pourovskii, CPHT-Ecole Polytechnique, CNRS, Université Paris-

Saclay, France

Impact of electronic correlations on point-defect thermodynamics and

transport in iron metal

–4–

15:45 –16:10 Igor Nekrasov, Institute of Electrophysics Ural Branch RAS, Ekaterinburg

Magnetocaloric effect in strongly correlated systems

16:10 –16:40 Coffee break

16:40-17:55 Chair Vladimir Anisimov

16:40 –17:05 Alessandro Toschi, Institute of Solid State Physics, TU Wien, Austria,

Quantum many-body theory at the two-particle level

17:05 –17:30 Georg Rohringer, Vienna University of Technology, Wien, Austria

Impact of non-local correlations over different energy scales: a dynamical

vertex approximation study

17:30 –17:55 Alexey Rubtsov, Russia Quantum Center, Moscow, Russia

Modeling of the impurity dynamics in ultracold atomic media

18:00 –20:00 Poster session and reception (beer and food)

23 September

SESSION 2: MAGNETISM AND ALL THAT

10:00-12:20 Chair Alexander Lichtenstein

10:00 –10:40 Tamio Oguchi, ISIR, Osaka university, Japan

Electronic properties associated with spin-orbit coupling and broken symmetry

10:40 –11:05 Igor Solovyev, National Institute for Materials Science, Tsukuba, Japan

Origin and microscopic mechanisms of magnetoelectric coupling in

multiferroic manganites

11:05 –11:30 Vladimir Mazurenko, Ural Federal University, Ekaterinburg, Russia

Methods for calculation and analysis of the Dzyaloshinskii-Moriya interaction

–5–

11:30 –11:55 Mikhail Korotin, Institute of Metal Physics, Ekaterinburg, Russia

Coherent potential approximation for strongly correlated systems with spin-

orbit coupling

11:55 –12:35 Sergey Savrasov, University of California, Davis, CA, USA

Weyl semi-metal: a new topological state in condensed matter.

13:00 –14:00 Lunch

14:00-16:05 Chair Olle Eriksson

14:00 –14:25 Alexander Tsirlin, University of Augsburg, Augsburg, Germany

Ab initio evaluation and experimental verification of magnetic exchange

parameters in insulators

14:25 – 14:50 Sergey Skornyakov, Institute of Metal Physics, Ekaterinburg, Russia

Electronic correlations and topological Fermi surface transition in the iron-

based chalcogenides

14:50 – 15:15 Sergey Khmelevskyi, Vienna University of Technology, Wien, Austria

Functional antiferromagnetic materials for spintronics applications: challenge

for ab initio computations.

15:15 – 15:40 Tilmann Hickel, X. Zhang, J. Rogal, Jörg Neugebauer, MPIE, Dusseldorf,

Germany

The role of interfaces for structural transformations among austenite, ferrite

and cementite in Fe-C alloys


16:10 –18:40 Master class

Alexander Poteryaev, IMP Ural Branch RAS, Ekaterinburg, Russia

Application of the AMULET code for DFT+DMFT calculations of realistic

compounds

–6–

24 September

SESSION 3: ALLOYS, STRUCTURE AND ALL THAT

10:00-12:25 Chair Pavel Korzhaviy

10:00 –10:40 Jörg Neugebauer, A. Glensk, F. Koermann, B. Grabowski, T. Hickel, MPIE,

Dusseldorf, Germany

Ab initio thermodynamic description of advanced structural materials: Status

and challenges

10:40 –11:20 Igor Abrikosov, Linköping University, Linköping, Sweden

Finite temperature effects in ab initio simulations of alloy thermodynamics

11:20 –11:45 Alexander Rudenko, Radboud University, Nijmegen, Netherlands

Intrinsic transport properties of monolayer black phosphorus

11:45 –12:10 Danil Boukhvalov, Department of Chemistry, Hanyang University, Korea

Locally destroyed crystal order in Ti-Fe alloys.

12:10 –12:35 Alexander Mirzoev, A. Verkhovykh, South Ural State University,

Chelyabinsk, Russia

The interaction of hydrogen interstitials with grain boundaries in bcc iron

13:00 –14:00 Lunch

14:00-16:05 Chair Igor Abrikosov

14:00 –14:25 Sergey Simak, Linköping University, Linköping, Sweden

Temperature-driven martensitic phase transitions from first principles

14:25 –14:50 Vsevolod Razumovskiy, D. Scheiber, L. Romaner, Materials Center Leoben

Forschung GmbH (MCL), Leoben, Austria

Impurity segregation and its effect on the grain boundary embrittlement in Ti:

effects of chemical and structural contributions

14:50 –15:15 Nadezhda Medvedeva, Institute of Solid State Chemistry, Ekaterinburg, Russia

Ab initio simulation of phosphorus in bulks, at surfaces and interface of fcc Fe

and K-carbide

15:15 –15:40 Oleg Gorbatov, Institute of Quantum Materials Science, Ekaterinburg, Russia

Effect of composition on antiphase boundary energy in NI3AL based alloys

15:40 –16:05 Mikhail Petrik, Institute of Metal Physics Ural Branch RAS; Institute of

quantum materials science, Ekaterinburg, Russia

–7–

Ab initio investigation of grain boundary segregation in Al=X

(X=Mg,Zn,Si,Cu) alloys


16:30-18:40 Chair Yuri Gornostyrev

16:30 –17:10 James Morris, Oak Ridge National Lab, Oak Ridge, TN, USA

Ab initio modeling for understanding and predicting novel alloy behavior

17:10 –17:50 Pavel Korzhavyi, Royal Institute of Technology, Stockholm, Sweden

Ab initio based models of disordered materials

17:50 –18:15 Mikheil Sekania, University of Augsburg, Augsburg, Germany

Scaling behavior of the Compton profile of alkali metal elements

Poster Session and Reception

22 September, 18:00 – 20:00

1 V. Greshnyakov, E. Belenkov, Chelyabinsk State University, Chelyabinsk, Russia

Ab initio modelling of diamond-like materials

2 M. Shundalov, A. Matsukovich, S. Gaponenko, Belarusian State University; B.I.

Stepanov Institute of Physics, Minsk, Belarus

DFT and multi-reference perturbation theory calculations of the structures and uv-vis

spectra of adamantane-containing molecules, potential antibacterial agents

3 A. Gerasimov, V. Mazurenko, S. Skornyakov, Ural Federal University; Institute of Metal

Physics Ural Branch RAS, Ekaterinburg, Russia

Modelling of the magnetic interaction of strongly correlated systems

4 I. Kashin, I. Solovyev, V. Mazurenko, Ural Federal University, Ekaterinburg, Russia;

National Institute for Materials Science, Tsukuba, Japan

–8–

Effect of dynamical electron correlations on collective magnetic excitations in CrO2

5 S. Andreev, I. Solovyev, V. Mazurenko, Ural Federal University, Ekaterinburg, Russia;

National Institute for Materials Science, Tsukuba, Japan

Pressure dependence of the electronic structures of Sr3Ir2O7

6

O. Sotnikov, V. Mazurenko, Ural Federal University, Ekaterinburg, Russia

A method for calculating paramagnetic exchange interactions

7 I. Nekrasov, N. Pavlov, M. Sadovskii, A. Slobodchikov, Institute of Electrophysics of the

Ural Branch RAS; Institute of Metal Physics Ural Branch RAS, Ekaterinburg, Russia

The electronic structure of a monolayer FeSe on the SrTiO3 substrate

8 V.V. Bannikov, V.S. Kudyakova, A.A. Elagin, M.V. Baranov, A.R. Beketov , Ural

Federal University, Ekaterinburg, Russia; University of Michigan, USA; Hamburg

University, Germany

Electronic structure and magnetic properties of hexagonal and cubic modifications of

aluminium nitride doped with sp-impurities (B, C, O)

9 D. Medvedeva, V. Mazurenko, S. Iskakov, A. Lichtenstein, Ural Federal University,

Ekaterinburg, Russia; University of Michigan, USA; Hamburg University, Germany

Calculation scheme based on the extended equations of DMFT for square and triangular

lattices

10 J. Komleva, S. Nikolaev, A. Tsirlin, V. Mazurenko, Ural Federal University,

Ekaterinburg, Russia; University of Augsburg, Germany

Lattice dynamics in copper chloride CuCl2

11 D. Badrtdinov, S. Nikolaev, V. Mazurenko, Ural Federal University,

Ekaterinburg, Russia

Spin-orbit coupling effects in adatom systems Si(111):{C,Si,Sn,Pb}

12 D. Zakir’yanov, V. Chernyshev, Ural Federal University, Russia

Lead oxyhalides Pb3X2O2 (X=Cl, Br, I): ab initio calculations of phonon spectra and

optical properties

13 A. Stepanenko, D. Vesnina, P. Igoshev, A. Katanin, Ural Federal University, Institute of

Metal Physics Ural Branch RAS, Ekaterinburg, Russia

The Kohn anomalies in three-dimensional systems

14 V. Protsenko, A. Katanin, Institute of Metal Physics Ural Branch RAS; Ural Federal

University, Ekaterinburg, Russia

Electron transport through double quantum dots: the functional renormalization group

approach

–9–

15 D. Prishchenko, A. Rudenko, V. Mazurenko, M. Katsnelson, Ural Federal University,

Ekaterinburg, Russia; Radboud University, Nijmegen, Netherlands

Plasmons and screening in phosphorus: beyond wavelength limit

16 S. Sozykin, V. Beskachko, South Ural State University, Chelyabinsk, Russia

Contacts of carbon and gold nanotubes: first principles calculations

17 I. Tikina, N. Barbin, Ural Institute of state fire service of EMERCOM of Russia; Ural

state agrarian University, Ekaterinburg, Russia

Thermodynamic modeling of thermal dissociation of the intermetallic compounds

PbBi2Sn2

18 M. Petrik, D. Badrtdinov, Institute of Metal Physics Ural Branch RAS; Institute of

quantum materials science; Ural Federal University, Ekaterinburg, Russia

Magnetic anisotropy effects in Fe-Ga alloys

19 D. Nazipov, A. Nikiforov, L. Gonchar, Ural Federal University; Ural State University of

Railway Transport, Ekaterinburg, Russia

Structure and lattice dynamics of BiMnO3: Ab initio calculations

20 V. Chernyshev, A. Nikiforov, V. Petrov, Ural Federal University, Ekaterinburg, Russia

Structure and lattice dynamics of PrFe3(BO3)4: Ab initio calculation

21 I. Leonidov, V. Petrov, V. Chernyshev, A. Ishchenko, E. Konstantinova, A. Nikiforov,

Institute of Solid State Chemistry UB RAS; Ural Federal University, Ekaterinburg,

Russia

Lanthanide-Doped Germanates: DFT Study of Lattice Dynamics and Electronic

Structure of Optical Hosts

22 Z. Pchelkina, O. Volkova, V. Mazurenko, A. Vasiliev, Institute of Metal Physics Ural

Branch RAS, Ural Federal University, Ekaterinburg, Lomonosov Moscow State

University, National University of Science and Technology “MISiS,” Moscow, Russia

Electronic structure and magnetic properties of the strong-rung spin-1 ladder

Rb3Ni2(NO3)7

23 I. Piterskikh, D. Boukhvalov, V. Mazurenko, Ural Federal University, Ekaterinburg,

Russia; Hanyang University, Seoul, Republic of Korea

Full potential study of electronic and magnetic properties of functionalized graphene

24 D. Suetin, Institute of Solid State Chemistry, Ural Branch RAS, Ekaterinburg, Russia

Structural, electronic properties, stability and fermi surfaces of ternary borides CaM2B2,

CaM3B2, Ca2M5B4, Ca3M8B6 (M = Rh, Ir)

25 M. Ivonina, P. Snegurov, V. Sizov, Saint Petersburg State University, Saint Petersburg,

Russia

Oxygen ion diffusivity in scandia-stabilized zirconia: molecular dynamics simulations

–10–

and ab initio calculation

26 L. Kar’kina, I. Kar’kin, A. Kuznetsov, Institute of Metal Physics Ural Branch RAS;

Institute of quantum materials science, Ekaterinburg, Russia

Atomistic simulation of stacking faults in cementite

27 A. Stroev, Yu. Gornostyrev, Institute of Metal Physics Ural Branch RAS; Institute of

quantum materials science, Ekaterinburg, Russia

Precipitation kinetics and GPZ formation in Al-based alloys. Master equation approach

with ab-initio parameterization

28 I. Shmakov, I. Razumov, Yu. Gornostyrev, Institute of Metal Physics Ural Branch RAS;

Institute of quantum materials science, Ekaterinburg, Russia

Decomposition kinetics in Fe–Cu dilute alloys. Monte Carlo simulations

29 K. Nekrasov, N. Kichigina, Ural Federal University, Ekaterinburg, Russia

Molecular dynamics simulation of bulk xenon diffusion in UO2: a comparison of ab initio

interaction potentials

30 I. Lomaev, D. Novikov, S. Okatov, Yu. Gornostyrev, S Burlatsky, Institute of Quantum

Materials Science, Institute of Metal Physics UB RAS, Ekaterinburg, Russia, United

Technologies Research Center (UTRC), USA

Size misfit versus electronic effects in diffusion of substitutional impurities in ni matrix

31 A. Kardashin, V. Mazurenko, Ural Federal University, Ekaterinburg, Russia

Electronic and magnetic properties of iron impurities on W(110)

32 A. Pravednicov, A. Tsirlin, D. Prishchenko, V.G. Mazurenko, Experimental Physics VI,

Center for Electronic Correlations and Magnetism, Institute of Physics, University of

Augsburg, Germany; Ural Federal University, Ekaterinburg, Russia

Modeling the electronic structure and dynamics of the crystal lattice TiPO₄

ABSTRACTS

INVITED AND CONTRIBUTED TALKS

AB INITIO BASED MODELING OF ADVANCED MATERIALS 2016

–12–

STRONG ELECTRONIC CORRELATIONS IN MAGNETIC MATERIALS

Alexander Lichtenstein,

University of Hamburg, Germany

Effects of electron interactions in magnetic materials, oxides and transition metals will

be discussed. Modern density functional theory describes well the ground state properties for

moderate correlated metals, but failed for some Mott insulators. Spectroscopy of strongly

correlated magnetic materials with transition or rare-earth elements can be well incorporated

only in correlated electronic structure scheme. We introduce a multi-orbital spin-polarized

dynamical mean field theory which allowed investigating the correlations effects in real

materials. Prospects of realistic description of itinerant magnetism in transition metals and Mott

insulators state in complex oxides will be discussed.

*Email: [email protected]


–13–

NON-LOCAL EFFECTS IN STRONGLY-CORRELATED SYSTEMS Andrey Katanin1,2

1Institute of Metal Physics, 620990, Ekaterinburg, Russia

2Ural Federal University, 620002, Ekaterinburg, Russia

We consider non-local effects in strongly-correlated systems and theoretical approaches,

which allow for their description based on dynamical mean-field theory as a starting point.

Although some of such approaches ((E)DMFT+GW, dynamic vertex approximation, dual

fermion/boson approaches) are known for relatively long time, we consider newer DMFT+spin-

fermion model, DMF2RG, and (E)DMFT+2PI fRG approaches.

In the first part of the talk we discuss effects of non-local magnetic correlations in iron. As a

theoretical tool, we consider DMFT+spin-fermion model approach [1,2]. This approach allows

evaluating non-local (Heisenberg-type) exchange interactions and Curie temperature, which

agree well with existing estimates, but in addition one can obtain information on the non-local

contributions to energy, free energy, etc. This approach is also applied to describe non-local

correlations in the vicinity of - structural transformation in iron.

In the second part of the talk we consider theoretical approaches to screening of Coulomb

interaction beyond (E)DMFT+GW. In particular, we describe the (E)DMFT+2PI fRG approach

[3], which treats the self-energy and polarization operator corrections to DMFT, using functional

renormalization-group method for the two-particle irreducible vertices. Being close in spirit to

dynamic vertex approximation [4] from one side (regarding using of the two-particle irreducible

vertices) and DMF2RG approach [5] from the other side (regarding using functional

renormalization group method), the described approach allows treatment of non-local

interactions in correlated electronic systems in a scheme, which accounts for vertex corrections

over the standard applications of (E)DMFT+GW approach. The resulting equations and the

relation to the dual boson approach are discussed.

[1] Igoshev PA, Efremov AV, Katanin AA, Phys. Rev. B 2015; 91:195123

[2] Katanin AA, Belozerov AS, Anisimov VI, arXiv:1605.04589.

[3] Katanin AA, ArXiv: 1604.01702.

[4] Toschi A, Katanin AA, Held K, Phys. Rev. B 2007; 75:045118;

Toschi A, Rohringer G, Katanin AA, Held K, Ann. der Phys. 2011; 523:698.

[5] Taranto C, Andergassen S, Bauer J, Held K, Katanin A, Metzner W, Rohringer G, Toschi

A, Phys. Rev. Lett. 2014; 112:196402.



–14–

ELECTRONIC STRUCTURE AND PHASE STABILITY OF

CORRELATED ELECTRON MATERIALS UNDER EXTREME

CONDITIONS Ivan Leonov 1,2*

1 Theoretical Physics III, Center for Electronic Correlations and Magnetism, University of

Augsburg, Germany 2 Materials Modeling and Development Laboratory, National University of Science and

Technology 'MISIS', 119049 Moscow, Russia

Computational studies of electronic correlations and magnetism and, in particular, a realistic

modelling of strongly correlated electron materials, is a challenging theoretical problem. In this

talk, I will discuss an application of the novel computational scheme LDA+DMFT to explore the

electronic and structural properties of correlated materials [1]. In particular, I will present our

recent results for the pressure-induced magnetic collapse and Mott insulator-metal transition in

paramagnetic oxides MnO, FeO, CoO, and NiO, and the electronic structure and phase stability

of Fe2O3 near a pressure-induced Mott metal-insulator transition. Our results for the electronic

state, the equilibrium crystal structure, and the structural phase stability are in quantitative

agreement with experimental data. We find that electronic correlations are important to explain

the lattice stability of correlated materials.

[1] Leonov I, et al, Phys Rev Lett 2011; 106:106405; Leonov I, et al, Phys Rev Lett 2014;

112:146401; Leonov I, et al, Phys Rev Lett 2015; 115: 106402; Leonov I, et al, Phys Rev B

2015; 91:195115.



–15–

MOLECULAR ORBITALS IN HEXAGONAL RUTHENATES Sergey Streltsov 1*, Igor Mazin 2

1 Institute of Metal Physics Ural Branch RAS, Russia

2 Naval Research laboratory, USA

We show that unique magnetic properties properties of several layered hexagonal ruthenates

including Li2RuO3 and SrRu2O6 can be explained basing on the conception of the molecular

orbitals. In Li2RuO3 formation of the molecular orbitals results in dimerization, appearance of

the spin gap and strong decrease of the magnetic susceptibility. Surprisingly, molecular orbitals

survive even at much higher temperature, where valence bond liquid state stabilizes. In this state

thermal fluctuations drive resonance between different dimer coverages, a classic analog of the

resonating valence bond state often discussed in connection with high-Tc cuprates [1].

Very different situation is observed in SrRuO6, which attract a lot of attention due to

surprisingly large Neel temperature ~550K despite of the layered structure. First principles

calculations show that only an ideal Neel ordering in the Ru plane is possible, with no other

metastable magnetic solutions, and, highly unusually, yield dielectric gaps for both

antiferromagnetic and nonmagnetic states. We demonstrate that this strange behavior is the

result of the formation of very specific electronic objects, molecular orbitals, whereby each

electron is well localized on a particular Ru6 hexagon, and completely delocalized over the

corresponding six Ru sites, thus making the compound both strongly localized and highly

itinerant [2].

[1] Kimber S.A.J., Mazin I.I., Shen J., Jeschke H.O., Streltsov S.V., Argyriou D.N., Valenti R.,

Khomskii D.I., Phys. Rev. B 2014 89: 081408

[2] Streltsov S., Mazin I.I., Foyevtsova K. Phys. Rev. B 2015, 92:134408



–16–

MAGNETIC AND STRUCTURAL PROPERTIES OF IRON AND ITS

ALLOYS IN LDA+DMFT Vladimir Anisimov

Institute of Metal Physics Ural Branch RAS, Ekaterinburg, Russia

Iron is a metal with a well-defined local moment and its magnetic properties above the Curie

temperature can be well described by LDA+DMFT method. We discuss the problem of

determining the values of direct and exchange Coulomb parameters U and J and dependence of

the calculation results on them. Correlation effects strongly influence not only magnetic but also

structural properties of iron. We present results of LDA+DMFT calculations for alpha-gamma

and gamma-delta transitions. Combination of Coherent Potential approach (CPA) with

LDA+DMFT allows treating correlation effects for alloys of iron. It was applied to the problem

of structural transition in iron-manganese alloy and also to calculation of Curie temperature for

iron-nickel alloy.



–17–

THEORY OF X-RAY AND PHOTOELECTRON SPECTROSCOPY WITH

DMFT Olle Eriksson

Department of Physics and Astronomy, Uppsala university, Uppsala, Sweden

In this talk I will present the basic ideas of dynamical mean-field theory (DMFT) and its

implementation in a full-potential electronic structure method that uses linear muffin-tin orbitals

as basis functions. Examples of DMFT calculations of the electronic structure calculated will be

given, for rare-earth as well as transition metal oxides. For several materials I will compare the

DMFT results to more traditional calculations like LSDA and LDA+U. The extension of this

theory to describe x-ray absorption processes will also be given with calculated examples from

the transition metal monoxides. The class of materials covered in this talk range from bulk to

clusters.



–18–

IMPACT OF ELECTRONIC CORRELATIONS ON POINT-DEFECT

THERMODYNAMICS AND TRANSPORT IN IRON METAL Leonid Pourovskii

CPHT-Ecole Polytechnique, CNRS, Université Paris-Saclay,

F-91128 Palaiseau, France

We apply an ab initio theoretical framework combining the density functional and dynamical

mean field theories (DFT+DMFT) to study point-defect thermodynamics and transport

properties of elemental iron.

First, we consider hexagonal close-packed ε-iron at the Earth's core volume and for

temperatures up to 7000K [1]. We find that highly compressed ε-Fe behaves as a nearly perfect

Fermi liquid with the corresponding Fermi-liquid temperature scale TFL of about 14000 K, i.e.

much higher than the possible temperature range for the core. The calculated electron-electron-

scattering contribution to the electrical resistivity is rather insignificant compared to the

electron-phonon one. However, we find that the electron-electrons-scattering still quite

important for the thermal resistivity of ε-Fe, which is greatly enhanced due to the Fermi-liquid

quadratic frequency dependence of the scattering rate. Hence, the Fermi liquid behavior causes

the calculated thermal resistivity to be of comparable magnitude to the electron-phonon one.

One may expect a significant impact due to this effect on the dynamics of Earth’s core.

Another application of the same approach concerns the single-vacancy formation energy in

α-Fe at ambient conditions. We find that the vacancy formation energy is substantially reduced

as compared to previous standard density-functional theory calculations, with the obtained

theoretical value being in excellent agreement with experiment. The reduction is found to be

induced by enhancement of correlations at the vacancy's nearest-neighbors; this enhancement is

explained by subtle changes in the corresponding local density of states of d-electrons. Local

lattice relaxations around the vacancy are substantially enhanced by many-body effects.

[1] Pourovskii LV, Mravlje J, Georges A, Simak SI, Abrikosov IA, arXiv:1603.02287v3



–19–

INVESTIGATION OF MAGNETOCALORIC EFFECT IN CORRELATED

METALLIC SYSTEMS

Igoshev P.A.1,2, Kokorina E.E.2, Lei Xue3, Nekrasov I.A.2

1Institute of Metal Physics UB RAS, Ekaterinburg, Russia 2Institute of Electrophysics UB RAS, Ekaterinburg, Russia

3Ural Federal University, Ekaterinburg, Russia

In this work we systematically investigated change of entropy S within magnetocaloric

effect for ferromagnetic correlated metallic systems with van Hovwe singularities in the bare

spectra. It was done in the frame of single band Hubbard model within mean-field

approximation. For this model the expression for S can be obtained analytically. Analysis of

the solution of the model shows that in contrast to the Heisenberg model here S strongly

depends not only on spin value and Curie temperature but also on bare electronic structure. This

fact gives additional possibilities to make magnetocaloric effect stronger.

Numerical calculations of S were done for different values of model parameters: small

enough Coulomb interaction U, hopping integrals t and t' and occupancies n. All calculations

were performed for the infinite dimensions Bethe lattice. It is shown that for the case of second

order magnetic phase transition the change of entropy S is always negative for any set of model

parameters. Maximum value of S naturally appearing near Curie temperature is found to

become even stronger while approaching van Hove singularity.

Also in this work magnetocaloric effect is studied for the case of first order magnetic

phase transition. Phase separation region was found as a function of U and n for different t'/t

ratios. Interestingly that in contrast to the second order magnetic phase transition the S value

changes sign in the phase separation region with U or n change. This theoretically allows one

some practical application as, for example, thermo stabilizing system.

To overcome mean-field approximation restrictions magnetocaloric change of entropy

DS was also investigated within dynamical mean-field theory (DMFT).



–20–

QUANTUM MANY-BODY THEORY AT THE TWO-PARTICLE LEVEL

Alessandro Toschi

Institute of Solid State Physics, TU Wien, Austria

Our physical understanding is mostly based on the quantum many - body

description at the one or at the two-particle level. For strong correlations, the dynamical mean-

field theory (DMFT), a self-consistent approach at the one-particle level, has represented a big

step forward in the last two decades. Recently, however, the scientific frontier has moved to the

treatment of correlations at the two-particle level [1]. This represents a key progress to

understand spectroscopic experiments beyond photoemission [2] and to correctly capture

magnetic screening processes in correlated metals [2,3]. Furthermore, it provides new tools [4]

for a quantitative identification of the fluctuations responsible of characteristic features of

correlated spectral functions, such as, e.g., the pseudogap in the cuprates. Finally, it allows to

study non-local correlations on all length-scales through diagrammatic extensions of DMFT,

such as the dynamical vertex approximation (DΓA) [5]. By means of DΓA, the "fate"

of the Mott-transition in two dimensions [6] and the critical exponents of the Hubbard model in

three dimensions can be calculated [7], opening promising perspectives [8] for non-perturbative

treatments of quantum phase transitions.

G. Rohringer, A. Valli, and A. Toschi, Phys. Rev. B 86, 125114 (2012);

T. Schäfer, et al., Phys. Rev. Lett. 110, 246405 (2013).

A. Toschi, et al., Phys. Rev. B 86, 064411 (2012).

A. Hausoel, et al., submitted; A. Galler, et al., Phys. Rev. B 92 205132 (2015).

O. Gunnarsson et al., Phys. Rev. Lett. 114, 236402 (2015); Phys. Rev. B (2016), in press.

A. Hausoel, et al., submitted; A. Galler, et al., Phys. Rev. B 92 205132 (2015).

A. Toschi, A. A. Katanin, and K. Held, Phys. Rev. B 75 045118 (2007).

T Schäfer, et al., Phys. Rev. B 91, 125109 (2015).

G. Rohringer, A. Toschi, A. Katanin, and K. Held, Phys. Rev. Lett. 107, 256402 (2011).

T.Schäfer, A. Katanin, K. Held, and A. Toschi, arXiv:1605.06355, submitted.



–21–

IMPACT OF NON-LOCAL CORRELATIONS OVER DIFFERENT

ENERGY SCALES: A DYNAMICAL VERTEX APPROXIMATION

STUDY Georg Rohringer 1,2*, Alessandro Toschi 1

1 Institute of Solid State Physics, Vienna University of Technology, Austria

2 Russian Quantum Center, Russia

In this work [1], we investigate how non-local correlations affect selectively, the

physics of correlated electrons over different energy scales, from the Fermi level to the

band-edges. This goal is achieved by applying a diagrammatic extension of dynamical

mean field theory (DMFT), the dynamical vertex approximation (DA) [2,3], to study

several spectral and thermodynamic properties of the unfrustrated Hubbard model in two

and three dimensions. Specifically, we focus first on the low-energy regime by computing

the electronic scattering rate and the quasiparticle mass renormalization for decreasing

temperatures at a fixed interaction strength. This way, we obtain a precise characterization

of the several steps, through which the Fermi-liquid physics is progressively destroyed by

non-local correlations. Our study is then extended to a broader energy range, by analyzing

the temperature behavior of the kinetic and potential energy, as well as of the corresponding

energy distribution functions. Our findings allow to identify a smooth, but definite

evolution of the nature of non-local correlations by increasing interaction: They either

increase or decrease the kinetic energy w.r.t. DMFT depending on the interaction strength

being weak or strong respectively. This reflects the corresponding evolution of the ground

state from a nested-driven (Slater) to a superexchange-driven (Heisenberg) antiferromagnet,

whose fingerprints are, thus, recognizable in the spatial correlations of the paramagnetic

phase. Finally, a critical analysis of our numerical results of the potential energy at the

largest interaction allows us to identify possible procedures to improve the ladder-based

algorithms adopted in the dynamical vertex approximation.

Rohringer G, Toschi A. arXiv: 1604.08748.

Toschi A, Katanin AA, Held K. Phys Rev B 2007; 75:045118.

Rohringer G, Toschi A, Katanin AA, Held K. Phys Rev Lett 2011; 107:256402.


https://arxiv.org/abs/1604.08748


–22–

MODELING OF THE IMPURITY DYNAMICS IN ULTRACOLD ATOMIC

MEDIA V.V. Vyborova 1,2, Y.E. Shchadilova 2,3, A.N. Rubtsov 1,2,4*

1 Moscow State University, Russia 2 Russia Quantum Center, Russia

3 Harvard University, USA 4 VNIIA, Russia

Polaronic problem, describing a massive impurity interacting with a bosonic field, was

first introduced in the context of electron-phonon interaction over 80 years ago. It appears

in many branches of physics, including the black-hole evolution, neutron stars, and many

condensed matter applications. A particular interest arises for polarons formed in artificial

media, such as ultracold atomic gases. These systems allows a sudden change of their

parameters, thus making a problem of the dynamics of polaron formation experimentally

relevant.

We present our studies of the polaron formation dynamics based on the dynamical

extension of the variational Feynman approach. In Feynman approach, the effect of the

bosonic bath is taken into account using the single Gaussian degree of freedom, which is

linearly coupled with the impurity. Parameters of the impurity are chosen according to the

Feynman's variational principle. This approach can be extended to a more general effective

bath, being an arbitrary Gaussian system with the Greens function G (that means an infinite

number of the effective degrees of freedom). Feynman's variational principle yields then

the condition <S>0/G-1=-G, where the average is over the trial Gaussian ensemble.

Moreover, the same equation can used to describe the real-time dynamics, as it follows

from the Schwinger Dyson equations.

For a Frohlich Hamiltonian, we end up with a simple analytical expression for a self-

energy. It allows us to roll out a self-consistent numerical procedure for the polaron

formation dynamics. We will present the time-dependence of the polaron mobility and its

effective mass. Possible auto-localization will be considered as well.



–23–

ELECTRONIC PROPERTIES ASSOCIATED WITH SPIN-ORBIT

COUPLING AND BROKEN SYMMETRY

Tamio Oguchi

The Institute of Scientific and Industrial Research,

Osaka University

Several peculiar electronic properties emerge from spin-orbit coupling (SOC). Rashba effect

is known to be of SOC-origin spin-splitting mechanism by an electric filed. Magnetoelectric

(ME) effect in multiferroics is a coupling between magnetic and electric degrees of freedom

often arising from SOC. The most important clue to the understanding of such SOC-driven

phenomena lurks in the symmetry of the system. In this talk, I will present our recent theoretical

studies on Rashba effect at surfaces and ME effect in non-polar oxides.



–24–

ORIGIN AND MICROSCOPIC MECHANISMS OF

MAGNETOELECTRIC COUPLING IN MULTIFERROIC MANGANITES

Igor Solovyev 1*

1 National Institute for Materials Science, Tsukuba, Japan

I will discuss key mechanisms of the magnetic inversion symmetry breaking and

magnetoelectric coupling in several prototypical types of multiferroic manganiets, originating

from the interplay between competing interatomic magnetic interactions and intraatomic Hund's

coupling. One important aspect of multiferroic research is the correct determination of the

magnetic ground state, which can be highly nontrivial. Particularly, I will argue that the spin-

spiral order, which is frequently anticipated in orthorhombic and some other compounds, is

strongly deformed by relativistic interactions and this deformation is primarily responsible for

the ferroelectric activity in these systems [1]. This analysis is based on the mean-field solution of

the low-energy electron model, derived from the first-principles calculations in the Wannier

basis. Another important question is the coexistence of ferroelectricity and ferromagnetism [2].

In this respect, I will show that an antiferromagnetic order, that breaks the inversion symmetry,

gives rise not only to the ferroelectric activity but also induces finite Dzyaloshinskii-Moriya

interactions, which can lead to the weak ferromagnetism. Such situation is expected in BiMnO3

[3]. Finally, I will present a microscopic model, which captures basis aspects of the

magnetoelectric coupling in manganites. This model is based on the Berry phase theory of the

electronic polarization, where the asymmetric spin-dependent change of the occupied Wannier

functions in evaluated in the framework of the double exchange theory [4]. Particularly, this

model suggests that for an arbitrary noncollinear magnetic structure in orthorhombic

manganites, propagating along the b axis and antiferromagnetically coupled along the c axis, the

polarization can be obtained by scaling the one of the E-type antiferromagnetic phase with the

prefactor depending only on the relative directions of spins and being the measure of the spin

inhomogeneity.

[1] Solovyev IV. Phys Rev B 2011; 83:054404.

[2] Solovyev IV. J Phys Condens Matter 2008; 20:293201.

[3] Solovyev IV, Phys Rev B 2015; 90:024417.

[4] Solovyev IV, Nikolaev SA. Phys Rev B 2014; 90:184425.



–25–

METHODS FOR CALCULATION AND ANALYSIS OF THE

DZYALOSHINSKII-MORIYA INTERACTION

Vladimir Mazurenko 1*

1 Ural Federal University, Russia

The Dzyaloshinskii-Moriya interaction (DMI) plays a crucial role in formation of complex

magnetic states of correlated materials, such as weak ferromagnetism in antiferromagnets, spin

spirals, topologically protected spin textures (skyrmions) in metallic ferromagnets and others.

The determination of this magnetic interaction taking into account hybridization, correlation and

spin-orbit coupling effects is a complex methodological and computational problem requiring a

whole arsenal of numerical techniques.

In my talk, I will discuss different approaches for calculating the Dzyaloshinkii-Moriya

interaction. For instance, the combination of the superexchange theory proposed in the seminal

work by T. Moriya1 and local density approximation taking into account the spin-orbit coupling

gives reliable results in the case of the one-band systems such as low-dimensional cuprates2,3

and nanomaterials with sp-electrons magnetism. For the multi-band systems with different

strength of the spin-orbit coupling and correlation effects the problem of the realistic simulations

of DMI can be solved by using the correlated band method proposed in work4. A special focus

of the talk will be on the analysis of the signs of the orbital contributions to the total anisotropic

exchange interaction.

[1] Moriya T. Phys Rev 1960; 120:91.

[2] Mazurenko VV, Skornyakov SL, Anisimov VI, Mila F. Phys Rev B 2008; 78:195110.

[3] Badrtdinov DI, Volkova OS, Tsirlin AA, Solovyev IV, Vasiliev AN, Mazurenko VV.

arXiv:1604.03333.

[4] Katsnelson MI, Kvashnin YO, Mazurenko VV, Lichtenstein AI. Phys Rev B 2010;

82:100403.



–26–

COHERENT POTENTIAL APPROXIMATION FOR STRONGLY

CORRELATED SYSTEMS WITH SPIN-ORBIT COUPLING

Michael A. Korotin

M.N. Mikheev Institute of Metal Physics, 620990 Ekaterinburg, Russia

The method for calculating the electronic structure of nonstoichiometric and

superstoichiometric compounds with strong electron correlations and spin-orbit coupling is

developed based on the coherent potential approximation. Coherent potential approximation

implemented in the formalism of temperature Green's functions in the basis of localized Wannier

functions. Principles of the method, including the method of accounting for the strong

correlations could be found in [1]. Spin-orbit interaction is as set forth in [2]. The method of

calculation of the parameter ΔV, which describes the characteristics of the potential difference

between the impurity atom and atom replaced by impurity, is discussed also.

As an example, Fig 1 demonstrates the energy dependence of calculated coherent potential

of s-states of an effective oxygen site in TiO2-δ. See [3] for details.

Fig. 1 Self-consistent coherent potential of s-states of effective oxygen site in dependence of

Matsubara frequencies (left) and of real energies (right) for nonstoichiometric rutile TiO2-δ.

Korotin MA, Pchelkina ZV, Skorikov NA, Kurmaev EZ, Anisimov VI. J. Phys.: Condens.

Matter 2014; 26:115501.

Korotin MA, Skorikov NA, Skornyakov SL, Shorikov AO, Anisimov VI. JETP Letters

2014; 100:823.

Korotin MA, Skorikov NA, Zainullina VM, Kurmaev EZ, Lukoyanov AV, Anisimov VI.

JETP Letters 2012; 94:806.



–27–

INTRINSIC TRANSPORT PROPERTIES OF

MONOLAYER BLACK PHOSPHORUS

Alexander N. Rudenko1*

1 Radboud University, Institute for Molecules and Materials,

Heijendaalseweg 135, 6525AJ, Nijmegen, The Netherlands

A few-layer black phosphorus (BP) is a novel 2D semiconductor with strongly anisotropic

electronic properties. Here, we address the problem of intrinsic mobility of single-layer BP

considering charge carrier scattering involving single- and two-phonon processes. We develop a

theory for phonon scattering in anisotropic 2D semiconductors and apply it to study intrinsic

transport in monolayer BP, for which relevant parameters we determine from first-principles

calculations [1]. We show that in contrast to graphene, where two-phonon processes due to the

scattering by flexural phonons dominate at any practically relevant temperature, two-phonon

scattering in BP is considerably less important compared to the single-phonon scattering

involving in-plane modes. This behavior is mainly attributed to a significant difference between

the elastic properties of graphene and BP. As a consequence, phonon-scattering in BP can hardly

be suppressed by depositing BP samples on substrates or by encapsulation. We also find that at n

= 1013 cm-2 and T = 300 K electron mobility in BP is significantly more anisotropic (μxx/μyy ~

6.2) than hole mobility (μxx/μyy ~ 1.4). In the same temperature and doping regime, absolute

values of μxx do not exceed 250 (700) cm2V-1s-1 for holes (electrons), which can be considered as

an upper limit for the mobility in BP at room temperature. Given that these values can be

considerably reduced by other intrinsic and extrinsic scattering mechanisms, the application of

BP as a high mobility semiconductor might be hindered.

[1] A.N. Rudenko, S. Brener, and M.I. Katsnelson, PRL 116, 246401 (2016).



–28–

AB INITIO EVALUATION AND EXPERIMENTAL VERIFICATION OF

MAGNETIC EXCHANGE PARAMETERS IN INSULATORS

Alexander A. Tsirlin1*

1 Experimental Physics VI, Center for Electronic Correlations and Magnetism, Institute

of Physics, University of Augsburg, Germany

Magnetism of real materials requires multiple parameters for a quantitative microscopic

description. While Heisenberg exchange J is often sufficient for predicting the type of magnetic

ground state, directions of the magnetic moments relative to the crystal axes are determined by

smaller anisotropy terms. In this talk, I will show how both isotropic and anisotropic exchange

couplings can be obtained from DFT-based band-structure calculations and verified by

experimental data, such as magnetization measurements and neutron scattering. Applications to

several frustrated magnets will be presented:

In kagome francisites Cu3Bi(SeO3)2O2X (X = Cl and Br) [1], Dzyaloshinsky-Moriya

interactions remove the extensive ground-state degeneracy induced by the frustrated kagome

geometry, and stabilize ferrimagnetic order, which is uncommon for cuprate compounds. The

magnetization process of francisites is highly anisotropic and conveys information about

anisotropic magnetic interactions in this system.

In Li2NiW2O8 [2], a sequence of commensurate and incommensurate magnetically ordered

phases is observed. This peculiar behavior is rationalized assuming a combination of the

magnetic frustration on the triangular spin lattice and a strong single-ion anisotropy driven by

geometrical distortions of NiO6 octahedra.

[1] Rousochatzakis I, Richter J, Zinke R, Tsirlin AA. Phys Rev B 2015; 91:024416.

[2] Ranjith KM, Nath R, Majumder M, Kasinathan D, Skoulatos M, Keller L, Skourski Y,

Baenitz M, Tsirlin AA. arXiv:1603.01811.



–29–

ELECTRONIC CORRELATIONS AND TOPOLOGICAL FERMI

SURFACE TRANSITION IN THE IRON-BASED CHALCOGENIDES

Sergey Skornyakov1*, Ivan Leonov 2, Vladimir Anisimov 1, Dieter Vollhardt 2


2 Theoretical Physics III, Center for Electronic Correlations and Magnetism, University

of Augsburg, Germany

We present results of a theoretical investigation of the electronic structure and phase stability

of the parent chalcogenide compound FeSe obtained within a combination of density functional

theory and dynamical mean-field theory [1]. Our results reveal an entire reconstruction of the

Fermi surface upon a moderate expansion of the lattice (Lifshitz transition), with a change of

magnetic correlations from the in-plane magnetic wave vector (π,π) to (π,0). We attribute this

behavior to a correlation-induced shift of the van Hove singularity originating from the xy and

xz/yz bands at the M-point across the Fermi level. We predict an isostructural transition of FeSe

upon a hydrostatic and uniaxial expansion of the lattice volume as well as a topological change

of the Fermi surface of FeSe upon partial substitution Se by Te, which is accompanied with a

sharp increase of the local moments. We expect that these changes are responsible for the

experimentally observed increase of the critical temperature in FeSe upon doping with Te. The

microscopic origin for superconductivity in this system is then due to a van Hove singularity

close to the Fermi level. This identification may open a new route to increase Tc even further.

[1] Leonov I, Skornyakov SL, Anisimov VI, Vollhardt D. Phys Rev Lett 2015; 115:106402.



–30–

FUNCTIONAL ANTIFERROMAGNETIC MATERIALS FOR

SPINTRONICS APPLICATIONS: CHALLENGE FOR AB INITIO

COMPUTATIONS

Sergii Khmelevskyi

Center for Computational Materials Science,

Vienna University of Technology, Austria

The antiferromagnetic materials become an ultimate importance in the modern electronics

since the discovery of the GMR effects. They provide a pining of the ferromagnetic layers and

being an integral part of almost any computer memory devices. Since the recent development

related to the possibility of the laser ultrafast switching of the magnetization in ferri- and

antiferromagnets (AFM), finding new routes for application of the spin-orbit coupling effects in

spintronic and abundance of the critical elements on the market – currently the search and design

of new AFM materials for applications, with stringent technological requirements on their

properties, is one of the main stream of the development in magnetic material science. In this

talk I will give an overview of the subject and illustrate a major role that the first-principles

modeling have in the AFM material development. The discovery of the new high-temperature

AFM materials, the funding of new routes in spintronics using ab initio modeling, application of

the magnetic force theorem for predicting the Neél temperature and local anisotropies in

functional AFM alloys on real examples (Mn2Au, Ru2MnX, V3Al, Mn3Ga, binaries

Mn(Ir,Pd,Ni) etc.) will be presented and discussed.



–31–

THE ROLE OF INTERFACES FOR STRUCTURAL

TRANSFORMATIONS AMONG AUSTENITE, FERRITE AND

CEMENTITE IN Fe-C ALLOYS

Tilmann Hickel, Xie Zhang, Jutta Rogal, Jörg Neugebauer

Max-Planck-Institut für Eisenforschung, Düsseldorf, Germany

During the cooling process of Fe-C alloys a decomposition of the high-temperature

austenitic phase into ferrite and cementite takes place. The atomistic modelling of the involved

processes at the interface is challenged by the simultaneous changes in Fe lattice and

redistribution of C to accommodate the reduced C solubility.

With a combination of the orientation relationships between austenite, ferrite and cementite,

we identify an intermediate structure, which serves as a link between the three phases. It is

extended over a few atomic layers and stabilizes the interfaces similar to complexions. Based on

this framework, different mechanisms depending on the local conditions (C concentration,

strain, magnetism) are revealed from ab initio nudged elastic band simulations, which allow us

to construct a theory for the structural transformations among austenite, ferrite, cementite and

martensite.



–32–

APPLICATION OF THE AMULET CODE FOR DFT+DMFT CALCULATIONS

OF REALISTIC COMPOUNDS

Alexander Poteryaev1


Over last twenty years, the DFT+DMFT method has successfully applied for a description

of different properties of strongly correlated materials [1,2]. This combination of the density

functional theory (DFT) to characterize material specific aspect of problem and the dynamical

mean field theory (DMFT) to treat strong electronic correlations allows one to understand a

physics of many systems. In this hands-on, we present Advanced Materials simULation

Ekaterinburg's Toolbox (AMULET [3]) - a suite of computer codes for ab initio DFT+DMFT

calculations. Electronic, magnetic and structural properties of realistic strongly correlated

compounds or alloys can be easily investigated with this instrument. During the session, the

DFT+DMFT and CPA+DMFT approaches will be considered in brief, while the main focus will

be on practical aspects. Participants will learn how AMULET interfaces with different band

structure packages. In a practical computer based part of hands-on, they will get skills on setting

up input files, running code and understanding results. Particularly, we consider in details the

FexNi1-x alloy [4] and calculate magnetic properties of this compound as function of

concentration.

[1] Anisimov V., Poteryaev A., Korotin M., Anokhin A., and Kotliar G., Journal of Physics:

Condensed Matter 9, 7359 (1997).

[2] Lichtenstein A. and Katsnelson M., Physical Review B 57, 6884 (1997).

[3] www.amulet-code.org

[4] Poteryaev A., Skorikov N., Anisimov V., and Korotin M., Physical Review B 93, 205135

(2016).



–33–

AB INITIO THERMODYNAMIC DESCRIPTION OF ADVANCED

STRUCTURAL MATERIALS: STATUS AND CHALLENGES

Jörg Neugebauer, Albert Glensk, Fritz Koermann, Blazej Grabowski

and Tilmann Hickel

Max-Planck-Institut für Eisenforschung, Düsseldorf, Germany

Modern engineering materials have evolved from simple single phase materials to nano-

composites that employ dynamic mechanisms down to the atomistic scale. The structural and

thermodynamic complexity of this new generation of structural materials presents a challenge to

their design since experimental trial-and-error approaches as successfully used in the past are

often no longer feasible. Ab initio approaches provide perfect tools to new design routes but face

serious challenges: Free energies of the various phases are almost degenerate, requiring

theoretical formalisms that accurately capture all relevant entropic contributions due to

electronic, vibrational or magnetic excitations, as well as their coupling such as phonon-phonon,

magnon-phonon interactions or spin-quantization. In addition, their hierarchical nature with

respect to length and time makes them challenging for any atomistic approach. Combining

accurate first principles calculations with mesoscopic/macroscopic thermodynamic and/or

kinetic concepts allows us now to address these issues and to determine free energies and

derived thermodynamic quantities that often rival available experimental data. The flexibility

and the predictive power of these approaches but also their present limitations will be discussed

for examples ranging from modern ultra-high strength steels to light weight metallic alloys.



–34–

FINITE TEMPERATURE EFFECTS IN AB INITIO SIMULATIONS OF

ALLOY THERMODYNAMICS

Igor Abrikosov

Department of Physics, Chemistry and Biology (IFM), Linköping University,

SE-581 83 Linköping, Sweden

Ab initio electronic structure theory is known as a useful tool for prediction of materials

properties, for their understanding, as well as for determination of parameters employed in

higher-level modeling. However, majority of simulations still deal with calculations in the

framework of density functional theory (DFT) with local or semi-local functionals carried out at

zero temperature. In this talk, we present new methodological solutions, which go beyond this

approach and explicitly take into account finite temperature effects. Basic ideas behind novel

techniques for first-principles theoretical simulations of lattice dynamics, as well as their

coupling to systems with magnetic excitations and configurational disorder are introduced. The

capabilities of the Temperature Dependent Effective Potential (TDEP) method [1], the

Disordered Local Moment Molecular Dynamics (DLM-MD) [2], and the combined technique

[3] are demonstrated in applications for Ti-based alloys, iron carbides, transition metal nitrides

and their alloys [4].

O. Hellman, I. A. Abrikosov, and S. I. Simak, Phys. Rev. B 84, 180301(R) (2011); O.

Hellman, P. Steneteg, I. A. Abrikosov, and S. I. Simak, Phys. Rev. B 87, 104111 (2013);

O. Hellman and I. A. Abrikosov, Phys. Rev. B 88, 144301 (2013).

P. Steneteg, B. Alling, and I. A. Abrikosov, Phys. Rev. B 85, 144404 (2012).

N. Shulumba, B. Alling, O.Hellman, E. Mozafari, P. Steneteg, M. Odén, and

I. A. Abrikosov, Phys. Rev. B 89, 174108 (2014).

N. Shulumba, O. Hellman, L. Rogström, Z. Raza, F. Tasnadi, I. A. Abrikosov, and M.

Odén, Appl. Phys. Lett. 107, 231901 (2015).



–35–

WEYL SEMI-METAL: A NEW TOPOLOGICAL STATE

IN CONDENSED MATTER

Sergey Savrasov

University of California Davis, USA

Using first-principles electronic structure calculations we investigate novel phases that

emerge from the interplay of electron correlations and strong spin-orbit coupling [1]. We focus

on describing the topological semimetal, a three-dimensional phase of a magnetic solid, which is

a three-dimensional analog of graphene with linearly dispersing excitations. This state provides

a condensed-matter realization of Weyl fermions that obeys a two-component Dirac equation. It

also exhibits remarkable topological properties manifested by surface states in the form of Fermi

arcs, which are impossible to realize in purely two-dimensional band structures. We discuss that

it may be realized in a class of pyrochlore iridates (such as Y2Ir2O7) based on calculations using

the LDA +U method and overview some recent experimental discoveries of Weyl semimetal

materials.

Xiangang Wan, Ari Turner, Ashvin Vishwanath, Sergey Y. Savrasov, Phys. Rev. B 83,

205101 (2011).



–36–

LOCALLY DESTROYED CRYSTAL ORDER IN Ti-Fe ALLOYS

D. W. Boukhvalov1, Yu. N. Gornostyrev,2,3 and M. I. Katsnelson4

1Department of Chemistry, Hanyang University, Seoul, Korea. 2Institute of Metal Physics, UB of RAS, Ekaterinburg, Russia 3Institute of Quantum Materials Science, Ekaterinburg, Russia

4Radboud University, Institute for Molecules and Materials, Nijmegen, Netherlands

Titanium-based alloys of transition metals demonstrate unusual (for metallic systems)

properties such as negative temperature coefficient of resistivity, pseudogap in infrared optical

spectra, strong concentration anomalies of sound velocities and attenuation, etc. We present the

results of ab initio modeling of structure of Ti-Fe, a typical representative of quenched Ti-based

transition-metal alloys. We have demonstrated that beyond the solubility limit this alloy cannot

be described in common terms of substitutional and interstitial alloys. Instead, very stable local

clusters are formed in both hcp and bcc matrices, with almost identical structures. This gives an

example of geometrically frustrated state and explains unusual concentration behavior of

Mössbauer spectra discovered long ago for this system.



–37–

TEMPERATURE-DRIVEN MARTENSITIC PHASE TRANSITIONS

FROM FIRST PRINCIPLES

Sergei I. Simak 1*

1 IFM, Linköping University, SE-58183 Linköping, Sweden

We discuss how a martensitic phase transition can be studied from first principles in the

framework of molecular dynamics, which allows for a proper account of temperature. As an

example the martensitic phase transition in the shape-memory alloy NbRu is considered. Its

thermophysical properties are reproduced in good agreement with experiment and the effect of

chemical disorder on the mechanical stability is elucidated.



–38–

IMPURITY SEGREGATION AND ITS EFFECT ON THE GRAIN

BOUNDARY EMBRITTLEMENT IN TI: EFFECTS OF CHEMICAL AND

STRUCTURAL CONTRIBUTIONS.

Vsevolod Razumovskiy, D. Scheiber, L. Romaner

Materials Center Leoben Forschung GmbH (MCL), Austria

In this paper we perform a series of density functional theory (DFT) calculations to

investigate segregation of 3d, 4d and 5d alloying elements to grain boundaries (GB) in bcc, fcc

and hcp Ti. We study the effect of these elements on GB cohesion and analyze the role of

structural and chemical contributions to the GB strengthening energy. The free surface and GB

segregation energies are analyzed by comparing results of DFT calculations to results of existing

physical segregation models. Following the concept of low-alloying additions proposed in Ref

[1], we suggest a list of the most promising alloying elements from the point of view of GB

cohesion enhancement in bcc, fcc and hcp Ti.

[1] V.I. Razumovskiy, A. Y. Lozovoi, I. M. Razumovskii Acta Mater. 82 (2015) 369-377



–39–

THE INTERACTION OF HYDROGEN INTERSTITIALS WITH

GRAIN BOUNDARIES IN BCC IRON Anastasiya Verkhovykh, Alexander Mirzoev*

South Ural State University, Russia

Hydrogen that is accumulated within the grain boundaries (GB) can lead to a decrease of the

critical strain required to fracture the material. The paper presents result of modeling of

hydrogen–grain boundary interaction in ferromagnetic bcc iron. Modeling was performed using

density functional theory with generalized gradient approximation (GGA’96), as implemented in

WIEN-2k package. Three fully relaxed tilt grain boundaries, Σ5(310), Σ5(210) and Σ3(111),

were studied. The supercells contained 40–48 atoms, i.e. 20–24 atoms in each of the two

‘grains’. The cohesive energy CE and binding energy

BE of hydrogen to that determines the

strengthening or embrittling effect can be defined as follows: H H

C GB GB fs fsE E E E E (1) H H

B GB GB bulk bulkE E E E E (2)

where EGB and H

GBE are the total energies of the impurity-free GB supercell and of the same

supercell with one H interstitial, Efs and H

fsE are the total energies of the free surface supercell

and with one H interstitial, Ebulk and H

bulkE are the energies of the commensurate Fe bulk supercell

and with one H interstitial. The results of calculation by the formulas (1)- (2) shown in Table 1.

Table 1. The cohesive (ΔEC) and the binding energy (ΔEB) of hydrogen to grain boundary.

GB types ΔEC (eV) ΔEB (eV)

Our results Other

results

Our results Other

results

Σ5(310) 0,68 - 0,43 0,4 [3]

Σ5(210) 0,07 - 0,81 -

Σ3(111) 0,41 0,31[2] 0,39 0,49 [1]

Exp. - 0,51 [4]

This work was supported by Russian Science Foundation (grant №16-19-10252) and RFFI (№

16-03-00486).

Matsumoto R. et al. Prog. Nucl. Sci. Technol. 2011; 2: 9.

Tian Z.X. et al. J. Phys., Condens. Matter 2011; 23: 015501.

Du Y.A. et al. Phys. Rev. B 2011;84: 144121.

Ono K. and Meshii M. Acta Metal Mater. 1992;40:1357.


https://kias.rfbr.ru/Application.aspx?id=14341663


–40–

AB INITIO SIMULATION OF PHOSPHORUS IN BULKS, AT SURFACES

AND INTERFACE OF FCC Fe AND κ-CARBIDE

Nadezhda Medvedeva

Institute of Solid State Chemistry, Ural Branch RAS, Ekaterinburg, Russia

First-principles atomistic methods provide reliable information on the microscopic

mechanisms governing the phase stability, impurity partitioning as well as deformation behavior

of iron alloys with carbide precipitates. Much attention is paid to the mechanisms of fracture and

plasticity, which may be studied using ab initio calculations of cleavage and shear

characteristics. The modeling of alloying effect on the interfacial structure and bonding of

carbide/Fe is very important to elucidate the dislocation pinning mechanism. The knowledge of

interfacial bonding is important to predict characteristics of precipitation (nucleation, growth and

coarsening) as well as the embrittling potency of impurities. Ab initio density functional calculations were performed to study phosphorus effect on the

structural, electronic and magnetic properties of bulk, surface and interface of κ-carbide

(Fe3AlC) and fcc Fe. The aim of this study was to shed light on its behavior in austenitic alloys

with the κ-carbide particles, where phosphorus promotes both intergranular and transgranular

embrittlement. The binding energies were calculated for phosphorus in the substitutional and

interstitial positions in bulks/surfaces/interface to predict its stable occupation sites. Our results

indicate that P atoms occupy the substitutional positions in both bulks and repel each other in

fcc Fe, whereas they show a trend to ordering in κ-carbide that favors its formation. Phosphorus

in κ-carbide reduces sharply its cleavage characteristics. The microscopic mechanism of

phosphorus effect on intergranular cleavage was related to strong anisotropy of Fe-P bonds

leading to the appearance of large structural voids in κ-carbide. The interstitial octahedral sites

are most stable for phosphorus adsorption at the (001)Fe3AlC and (001)fcc Fe surfaces, whereas

substitution for Fe is preferable at the (001)Fe3AlC/(001)fcc Fe interface. A strong tendency for

phosphorus segregation at surface explains the embrittling transgranular behavior of

phosphorus.

N.I.M acknowledges the support from the Russian Foundation for Basic Research (Grant 14-03-

00324а)

Email: [email protected]


–41–

EFFECT OF COMPOSITION ON ANTI-PHASE BOUNDARY

ENERGY IN NI3AL BASED ALLOYS

Oleg I. Gorbatov1*, I. L. Lomaev1,2, Yu. N. Gornostyrev1,2

1 Institute of Quantum Materials Science, Russia


The effect of composition on the anti-phase boundary (APB) energy of Ni based L12-ordered

alloys is investigated by ab initio calculations employing the coherent potential approximation

[1]. The calculated APB energies for {111} and {001} planes reproduce experimental values of

the APB energy. The APB energies for the non-stoichiometric γ'-phase increase with Al

concentration and are in line with the experiment. The magnitude of the alloying effect on the

APB energy correlates with the variation of the ordering energy of the alloy according to the

alloying element's position in the 3d row. The elements from the left side of the 3d row increase

the APB energy of the Ni based L12-ordered alloys, while the elements from the right side

slightly affect it except Ni.

[1] Gorbatov OI, Lomaev IL, Gornostyrev YuN, Ruban AV, Furrer D, Venkatesh V, Novikov

DL, Burlatsky SF. Phys. Rev. B 93, 224106 (2016).



–42–

AB INITIO MODELING FOR UNDERSTANDING AND PREDICTING

NOVEL ALLOY BEHAVIOR

James R. Morris1,2

1Materials Science and Technology Division, Oak Ridge National Lab, Oak Ridge, TN 37830 2Materials Science and Engineering Department, University of Tennessee, Knoxville, TN 37996

Ab initio calculations, combined with experiment and also with longer length scale

modeling, provides critical information on the stabilization of particular phases and

microstructures, under various thermal and mechanical stresses. This talk will focus on

approaches for connecting these issues, with a particular focus on high entropy alloys (HEAs)

formed of a large number of near-equiatomic elements. These alloys pose new questions

concerning the ability to predict single phase materials in alloys with a large number of

components, particularly metastable phases. We demonstrate that high-throughput calculations

provide important predictive information as to which compositions may form single-phase solid

solutions, including those where Hume-Rothery considerations have been shown to be

inadequate. From these same calculations, effective Monte Carlo models have been used to

examine phase evolution of Al-containing HEAs that show a complex set of phase

transformations. These same materials exhibit unusual mechanical properties, including the

unusual combination of increased strength and ductility under cooling conditions. The materials

challenge traditional considerations of solid-solution hardening, and atomistic simulations may

provide critical insight into these processes.

This work has been supported by the U. S. Department of Energy, Office of Science, Basic

Energy Sciences, Materials Science and Engineering Division.



–43–

AB INITIO BASED MODELS OF DISORDERED MATERIALS

Pavel A. Korzhavyi 1,2*

1 KTH Royal Institute of Technology, Stockholm, Sweden


Ab initio simulations of disordered solids at finite temperatures are becoming an important

part of integrated computational materials engineering. The fundamental ab initio approach

allows one, in principle, to predict the properties of alloys as functions of composition and

temperature, thereby enabling computer-aided design of high-performance materials [1]. In

practice, fully detailed simulations require large computational resources in order to follow the

evolution of a complex system in the available phase space (comprising electronic, magnetic,

vibrational, and compositional degrees of freedom) [2,3]. Therefore it is important to develop

methodologies of coarse-graining, i.e. procedures to extract the most essential information about

the system’s behavior and represent it effectively, using a few leading variables, while

integrating out the rest of the variables as just contributing to the statistics. To keep the

predictive power on the ab initio level, these procedures should be mathematically well-defined

and physically sound [4]. The existing approaches to coarse-graining in the field of finite-

temperature modeling of metallic alloys will be briefly reviewed. Application examples of

effective-medium-based methods to describe the thermal properties of steel and high-

temperature alloys will be given; recent achievements and remaining challenges will be

discussed.

[1] Hickel T, Kattner UR, Fries SG. Phys. Status Solidi B 2014; 251:9.

[2] Körmann F, et al. Phys. Status Solidi B 2014; 251:53.

[3] Abrikosov IA, et al. Current Opinion in Solid State and Materials Science 2016; 20:85.

[4] Schmitz GJ, et al. JOM 2015; 68:70.



–44–

SCALING BEHAVIOR OF THE COMPTON PROFILE OF ALKALI

METAL ELEMENTS

Michael Sekania1,2,*, Wilhelm H. Appelt1,3, Dieter Vollhardt1, Liviu Chioncel 1,3

1 Center for Electronic Correlations and Magnetism,

Institute of Physics, University of Augsburg, D-86135 Augsburg, Germany 2 Andronikashvili Institute of Physics, Tamarashvili 6, 0177 Tbilisi, Georgia

3 Augsburg Center for Innovative Technologies,

University of Augsburg, D-86135 Augsburg, Germany

We investigate the electron momentum density and Compton profiles of alkali metals

employing density functional theory. We show that the Compton profiles can be modeled by a q-

Gaussian distribution, recently proposed by Tsallis in the context of generalized canonical

distributions. Our analysis shows that tails, typically ignored in the conventional studies of the

Compton profiles, contain significant information about the electron momentum distribution in

solids. Thereby we derive an unexpected scaling behavior of the Compton profiles of all alkali

metals (see also Fig. 1).

Fig. 1 Scaled Compton profiles vs. (𝑝𝑧𝑎0) for the scattering direction [111]. The element-specific

(𝑞, 𝛽) parameters are given in the figure.

[1] M. Sekania, W. H. Appelt, D. Benea, H. Ebert, D. Vollhardt, L. Chioncel, arXiv:1602.01855

[cond-mat.mtrl-sci]


http://arxiv.org/find/cond-mat/1/au:+Sekania_M/0/1/0/all/0/1

http://arxiv.org/find/cond-mat/1/au:+Appelt_W/0/1/0/all/0/1

http://arxiv.org/find/cond-mat/1/au:+Vollhardt_D/0/1/0/all/0/1

http://arxiv.org/find/cond-mat/1/au:+Chioncel_L/0/1/0/all/0/1


–45–

AB INITIO INVESTIGATION OF GRAIN BOUNDARY SEGREGATION

IN ULTRAFINE-GRAINED AL-X [X=Mg,Zn,Si,Cu] ALLOYS Mikhail Petrik 1,2*, Yuri Gornostyrev 1,2


2Institute of quantum materials science, Russia

Producing ultrafine-grained (UFG) alloys by severe plastic deformation leads to segregation

of alloying elements at grain boundaries (GB), which considerably affects the material’s

properties. Ab initio calculations provide unique possibility to investigate processes of solute-

GB interactions accounting electronic and deformation mechanisms [1]. To understand main

experimental features of agglomeration formation we obtained ab initio results of interactions of

impurity atoms with the special type GB. Also the effect of GB presence on the solute-solute

interactions has been considered.

It is shown that electronic mechanisms of interaction between solutes prevail in Al-Zn and

Al-Cu alloys while the behavior of Mg solutes can be explained in deformation terms.

Segregation energy calculation showed that Mg atoms prefer to occupy the center of the GB as

well as the vicinity of the GB. Long-distance attractive Mg-Mg interactions near GB region lead

to heterogeneous agglomeration formation. In contrast, Zn atoms prefer to occupy interstitial

positions and are arranged into thin layers along GB. Accompanied with vacancy generation this

effect facilitates grain boundary sliding. Difference in chemical bonding of solute atoms X

[X=Mg,Zn,Si,Cu] with Al and its effect on the ductility of the alloys is discussed [2]. The results

obtained are consistent with experimental observation of super-strength in UFG Al-Mg alloys

and super-ductility in Al-Zn alloys.

L.E. Karkina, I.N. Karkin, A.R. Kuznetsova, , I.K. Razumov, P.A. Korzhavyi, Yu.N.

Gornostyrev Solute–grain boundary interaction and segregation formation in Al: First

principles calculations and molecular dynamics //Computational Materials Science, 112, 18-

26 (2016)

M. V. Petrik, A. R. Kuznetsov, N. Enikeev, Yu. N. Gornostyrev, R. Z. Valiev Ab initio

based analysis of grain boundary segregations in ultra-fine grained Al alloys // to be

published

*Email:[email protected]

http://www.sciencedirect.com/science/journal/09270256

ABSTRACTS

POSTERS


–47–

AB INITIO MODELLING OF DIAMOND-LIKE MATERIALS

Vladimir Greshnyakov*, Evgeny Belenkov

Chelyabinsk State University, Russia

Carbon diamond-like phases are phases consisting of four-coordinated carbon atoms.

Diamond-like phase structures can be theoretically obtained by linking or superpositioning of

precursors which are composed of three-coordinated atoms [1]. These precursors are graphene

layers, carbon nanotubes, fullerene-like clusters and three-dimensional graphites. Nanoclusters

of diamond-like phases have been obtained by this method, the structures of which were

geometrically optimized by semi empirical quantum mechanical methods [1, 2]. In the central

part of these clusters, the least distorted unit cells have been carved. Further, the unit cells were

geometrically optimized by density functional theory methods based on periodic boundary

conditions [3–6].

As a result of first-principles calculations, the possibility of stable existence of thirty-six

diamond-like phases is established (including the cubic diamond) [3–6]. The diamond-like phase

densities are in the range from 35 to 102 % relative to the diamond density. Sublimation

energies of these phases decrease with increasing the degree of structural tension of these phases

relative to the cubic diamond structure. Almost all of the diamond-like phases are wide bandgap

semiconductors with band gaps from 0.9 to 5.6 eV. Carbon diamond-like phases have high

mechanical characteristics: the bulk modulus varies from 141 to 452 GPa; the Vickers hardness

ranges from 49.4 to 90.1 GPa. The analysis of possible synthetic routes of the new phases has

shown that the phase transition of graphite into the cubic diamond or diamond-like phases

occurs at a pressure greater than 58 GPa. The calculated transition pressure value agrees well

with the experimental data (at P > 50 GPa and T < 300 K).

The research was funded by RFBR according to the research project No. 16-33-00030 mol_a.

[1] Greshnyakov VA, Belenkov EA. J Exp Theor Phys 2011; 113:86.

[2] Belenkov EA, Greshnyakov VA. J Struct Chem 2014; 55:409.

[3] Belenkov EA, Greshnyakov VA. Phys Solid State 2015; 57:205.

[4] Belenkov EA, Greshnyakov VA. J Mater Sci 2015; 50:7627.





–48–

DFT AND MULTI-REFERENCE PERTURBATION THEORY

CALCULATIONS OF THE STRUCTURES AND UV-VIS SPECTRA OF

ADAMANTANE-CONTAINING MOLECULES, POTENTIAL

ANTIBACTERIAL AGENTS

Maksim Shundalov 1*, Anna Matsukovich 2, Sergey Gaponenko 1,2

1 Belarusian State University, Minsk, Belarus

2 B.I. Stepanov Institute of Physics, NAS of Belarus, Minsk, Belarus

The incorporation of an adamantyl moiety into several molecules results in compounds with

relatively high lipophilicity, which in turn can modify the biological availability of these

molecules. Several adamantane derivatives were associated antimicrobial and anti-inflammatory

activities.

The structures of N'-(adamantan-2-ylidene)benzohydrazide (C17H20N2O, I, 4 conformers)

[1], 3-(adamantan-1-yl)-4-phenyl-1-[(4-phenylpiperazin-1-yl)methyl]-1H-1,2,4-triazole-5(4H)-

thione (C29H35N5S, II, 3 conformers) [2] and ethyl 4-{[3-(adamantan-1-yl)-4-phenyl-5-

sulfanylidene-4,5-dihydro-1H-1,2,4-triazol-1-yl]methyl}piperazine-1-carboxylate

(C26H35N5О2S, III, 6 conformers) [3] have been obtained at the B3LYP/cc-pVDZ level of

theory. The calculations of the UV-vis spectra for all conformers were performed at the

CASSCF/XMCQDPT2 [4] level of theory. The UV-vis absorption spectra of all compounds for

the ethanol solution were measured in the 200–450 nm region. The UV-vis spectrum (Fig. 1) of

the compound I in the 220–320 nm region reveals two bands that can be explained based on the

ab initio calculations of the “side” trans-conformers of the compound I at the MRPT level of

theory. For the compounds II and III we also obtained a good agreement between experimental

and calculated spectra.

Fig. 1 The absorption spectra of the compound I: experimental in ethanol (1)

and calculated at the CASSCF/XMCQDPT2 level of theory (2)

Almutairi M.S. et al. Acta Cryst. 2012; E68: o2247.

Al-Abdullah E.S. et al. Acta Cryst. 2012; E68: o345.

Al-Abdullah E.S. et al. Acta Cryst. 2012; E68: o531.

Granovsky AA. J. Chem. Phys. 2011; 134: 214113.



–49–

MODELLING OF THE MAGNETIC INTERACTION OF STRONGLY

CORRELATED SYSTEMS

Gerasimov A.O.1*, Mazurenko V.V.1*, Skornyakov S.L.2



This work is devoted to the implementation of the scheme for the calculation of the magnetic

interactions in strongly correlated materials. It shows unique electronic and magnetic properties

which can be used to create new technology. In such compounds at specific electronic states the

average value of the Coulomb interaction of the same order of magnitude as the kinetic energy,

so the construction of the perturbation theory in one of the parameters is not possible. A method

to solve this problem is - DMFT.

The developed numerical scheme includes:

Carrying out ab initio calculations using LDA;

The construction of the Hamiltonian in Hubbard model and the solution of the

Hamiltonian using numerical method DMFT;

Calculation of magnetic interactions on the basis of results of the DMFT-calculations

(Local forces theorem, see at [1]).

The scheme was tested on the BCC Fe crystal. One of the parameters for getting the

magnetic properties of strongly correlated systems is - the integral of the exchange interaction,

that was calculated (see at Fig.1) using the theorem of local forces [1]:

𝐽𝑖𝑗 = −𝑇𝑟𝜔𝐿(𝛴𝑖𝑆𝐺𝑖𝑗

↑ 𝛴𝑗𝑆𝐺𝑖𝑗

↓ ), (1)

where 𝛴𝑖𝑆 =

1

2(𝛴𝑖

↑ − 𝛴𝑖↓). The calculated Curie temperature with the exchange parameters from

Fig.1 is 966K, that close to that were obtained in [2] and to experimental 1045K [1].

In the future we plan to work to study the properties FeMn alloy.

Fig. 1 Exchange parameters in BCC Fe (in meV) as a function of shells ( = 10,

U = 2.3 eV, J = 0.9 eV).

[1] Katsnelson M. I., Lichtenstein A. I. Phys. Rev. B. 2000; 61:8906.

[2] Kvashnin Y. O., Granas O., Di Marco I. Phys. Rev. B. 2015; 91: 125133.



–50–

EFFECT OF DYNAMICAL ELECTRON CORRELATIONS ON

COLLECTIVE MAGNETIC EXCITATIONS IN CRO2

Ilya Kashin1*, Igor Solovyev 1, 2, Vladimir Mazurenko1

1 Department of Theoretical Physics and Applied Mathematics, Ural Federal University, Russia

2 National Institute for Materials Science, Japan

CrO2 is known to be a rare example of stoichiometric oxide, demonstrating half-metallic

(HM) and ferromagnetic (FM) properties. It is widely used in magnetic recording tape

production and serves as promising candidate for implementation in various spin-dependent

transport phenomena.

In this study we investigate the effect of dynamical electron correlations on the stability of

ferromagnetism in CrO2 by means of considering the collective magnetic excitations, such as

spin waves. For this purpose, we construct the realistic low-energy model for t2g band of Cr

atoms, derived from the first-principles electronic structure calculations, and solve it by means

of unrestricted Hartree-Fock approach (HF) and the dynamical mean-field theory (DMFT).

Obtained on-site Green’s function was used to calculate the interatomic exchange interactions in

the framework of the theory of infinitesimal spin rotations [1], which were combined to find the

value of spin stiffness constant. The results are shown at Fig. 1. Switching the sign of D to

negative in case of DMFT indicates that the strong antiferromagnetic longer-range exchange

interactions destabilize FM ground state. It leads to conclusion that accounting for dynamical

electron correlations is of the great significance to correctly describe the magnetic properties of

CrO2, the canonical and technologically important half-metallic ferromagnet.

Fig. 1 Spin stiffness constant in CrO2

This work is supported by a grant from Russian Foundation for Basic Research (Project № 16-

32-00076).

[1] Katsnelson MI, Lichtenstein AI. Phys Rev B 2000; 61:8906.



–51–

PRESSURE DEPENDENSE OF THE ELECTRONIC STRUCTURS OF

Sr3Ir2O7

Sergei Andreev 1*, Igor Solovyev 1, 2, Vladimir Mazurenko 1


2 National Institute for Materials Science, Japan

The iridium oxides with the Ruddlesden-Popper structure (Srn+1 Irn O3n+1) are in the focus of

modern condensed matter physics. It was shown that a strong spin-orbit coupling in these oxides

may lead to insulating state with a very narrow gap in the electronic spectrum [1]. This state can

be destroyed by applying the pressure. For Sr3Ir2O7 a structural transition was detected at a

pressure of 54 GPa at room temperature that is associated with the transition from the tetragonal

to monoclinic symmetry [2]. However, the changes in the spectrum of electron excitations

remain unknown.

The aim of the study is a theoretical description of the electronic and magnetic properties

under pressure. The LDA+U+SO calculations were conducted by using package Quantum-

Espresso. These calculations for the structures at different pressures revealed that the

compression of the unit cell is accompanied by an increase of the in-plane rotation angle of the

IrO6 octahedron, while the Ir-O distance decreases. The insulating state of Sr3Ir2O7 is therefore

very sensitive to the value of the pressure. We find a closure of the electronic gap and a

transition to a metallic state above 20 GPa. Another interesting result is a suppression of the

magnetic moment at high pressure.

This work was supported by grant RSF 14-12-00306.

[1] Witczak-Krempa W, Chen G, Kim YB, Balents L. Annu. Rev. Condens. Matter Phys 2014;

5:57.

[2] Donnerer C, Feng Z, Vale JG, Andreev SN, Solovyev IV, Hunter EC, Hanfland M, Perry

RS, Ronnow HM, McMahon MI, Mazurenko VV, McMorrow. arXiv:1508.04320v1.



–52–

A METHOD FOR CALCULATING PARAMAGNETIC EXCHANGE

INTERACTIONS

Oleg Sotnikov 1*, Vladimir Mazurenko 1


In this work, we introduce a method of exchange constants evaluation in paramagnetic

phase. It is based on suggestion that spin-spin correlation functions calculated within different

models are the same for system, described with these models. Performing high temperature

expansion of exponent in expressions of correlation functions one can obtain:

,ˆˆ))1((1)(2S

1 )12(

12

31L

LS

n

n

z

j

z

innij SSESS

J (1)

where S denotes on site spin, L is total number of lattice sites, En and n are excitation

energies and corresponding eigenstates of reference model Hamiltonian respectively. Using

equation (1), we evaluated exchange constants for spin rings and all-to-all systems having

S = 1/2. Half-filled Hubbard model has been used as reference for exchange constants

calculation. We compared eigenvalues spectra of both models in order to assess quality and

applicability of proposed method (Fig. 1). The results have also been checked with existing

approaches [1, 2] for evaluation of exchange constants.

Fig. 1 Nearest neighbor and next nearest neighbor exchange interactions of spin ring evaluated

by (1) for different parameters t and U of Hubbard model (a) and corresponding energy

excitation spectra (b).

The work is supported by the grant program of the Russian Science Foundation 15-12-20021.

[1] Anderson PW. Phys. Rev. 1959; 115:2.

[2] Liechtenstein AI, Katsnelson MI, et al. J. Magn. Magn. Mater. 1987; 67:65



–53–

THE ELECTRONIC STRUCTURE OF A MONOLAYER FeSe ON THE

SrTiO3 SUBSTRATE

I.A. Nekrasova, N.S. Pavlova, M.V. Sadovskiia,b, A.A. Slobodchikova*

aInstitute for Electrophysics, Russian Academy of Sciences, Ural Branch, Amundsen Str. 106,

Ekaterinburg, 620016, Russia

bM.N. Mikheev Institute for Metal Physics, Russian Academy of Sciences,

Ural Branch, S. Kovalevsky Str. 18, Ekaterinburg, 620290, Russia

The discovery of a new class of superconductors based on iron pnictides has opened up the

new prospects for the study of high-temperature superconductivity (cf. Reviews [1]). A

significant breakthrough in the study of iron based superconductors happened with the

observation of a record high Tc (higher than 50K) in epitaxial films of single FeSe monolayer on

a substrate of SrTiO3 (STO) [2].

To calculate electronic properties of the FeSe monolayer film on SrTiO3 substrate we used

the Quantum-Espresso package [3]. By looking on left panel of Fig.1 one can immediately

recognize that there appears an additional hole band near the M-point. To understand its origin

we plotted on right panel of Fig.1 O-2p states of topmost surface TiO2 layer of STO substrate.

We can conclude [4], that the presence of STO interface leads to the appearance of this

additional band of O-2p surface states near the Fermi level. Also we observe rather small

splitting of electron bands at M-point, which may have the relation to the observation of the

«replica» band at M-point [5], in contrast to optical phonons in STO scenario.

Fig. 1 (left) — LDA calculated band dispersion of FeSe monolaer on SrTiO3 substrate;

(right) — LDA calculated O-2p states of surface TiO2 layer of STO substrate.

Sadovskii M V. Usp. Fiz. Nauk 178 1243 (2008)

Wang Qing-Yan et al., Chin. Phys. Lett. 29 037402 (2012)

Giannozzi Paolo et al., J. Phys.: Condens. Matter 21 395502 (2009)

I.A. Nekrasov et al., arXiv:1605.02404

Lee J J et al., Nature 515 245 (2014)



–54–

ELECTRONIC STRUCTURE AND MAGNETIC PROPERTIES OF

HEXAGONAL AND CUBIC MODIFICATIONS OF ALUMINIUM

NITRIDE DOPED WITH SP-IMPURITIES (B, C, O)

V.V. Bannikov 1*, V.S. Kudyakova 2, A.A. Elagin2, M.V. Baranov 2, A.R. Beketov 2

1 Institute of Solid State Chemistry, Ural Branch RAS, Russia


The comparative modeling of band structure and magnetic properties of aluminium nitride

hexagonal and cubic modifications (w-AlN and r-AlN, respectively) with sp-impurities

(X=B,C,O) introduced into anionic sub-lattice (see Fig.1) has been performed by ab initio

FLAPW-GGA method. It was shown that the implantation of B or C into w-AlN results in spin

polarization of its near-Fermi electronic states, which is close to 100% (see Fig.2), as well, as in

considerable magnetic moments (~0.3–0.4 B) induced on the impurity atoms, so w-

AlN0.75(B,C)0.25 systems may be characterized as magnetic half-metals and so-called d0-

magnetics (see J.M.D. Coey, Sol. St. Sci., 7, 660 (2005)). However, this kind of situation does

not take place for cubic r-AlN0.75X0.25 systems predicted to be usual non-magnetic metals (see

Fig.2). The estimated substitution energies of X dopants for nitrogen in original structure are

~1.2-1.5 times higher for w-AlN0.75(B,C)0.25 systems as compared with r-AlN0.75(B,C)0.25,

indicating that the formation of the latter ones is expected to be more preferable. From the other

hand, the energy of oxygen substitution for r-AlN is ~1.5 times higher than for w-AlN, so the

metastable r-AlN phase is expected to be more resistant to oxidation processes than w-AlN is.

Fig. 1 The extended cells of

r-AlN0.75X0.25 (upper) and w-

AlN0.75X0.25 (lower).

Fig. 2 Spin-polarized densities of electronic states calculated for

w-AlN0.75X0.25 (upper row) and r-AlN0.75X0.25 (lower row). a:

X=B; b: X=C.



–55–

CALCULATION SCHEME BASED ON THE EXTENDED EQUATIONS

OF DMFT FOR SQUARE AND TRIANGULAR LATTICES

Daria Medvedeva 1*, V.V. Mazurenko1, S.N. Iskakov1,2, A.I. Lichtenstein1,3


2 Department of Physics, University of Michigan, USA

3 Hamburg University, Germany

DMFT is successful route for description of strongly correlated systems, which can exhibit

some of the most intriguing features known to condensed matter physics, including high-

temperature superconductivity, heavy fermion behavior, metal-insulator transitions and others

[1]. However, there are many examples when one should overcome the main limitation of the

DMFT that is neglect of the non-local magnetic and charge correlations. This is the case for

graphene-based systems for which strong inter-site Coulomb correlations [2] and magnetic

couplings [3] were found. To solve this problem one can use different extensions and

modifications of the single-site DMFT approach that are cluster DMFT[4], dual fermions

approach[5] and others.

In this work we propose a distinct numerical scheme based on the exact diagonalization

approach to solve the equations of the extended dynamical mean-field theory. In contrast to the

single-site DMFT we deal with the impurity problem where the correlated site interacts both

with fermion and boson reservoirs.

As a result, one can see that the account of the non-local magnetic interactions, leads to

the formation or gain of the low-energy peaks of the local magnetic susceptibility.

[1] A. Georges, G. Kotliar, W. Krauth and M.J. Rosenberg, Review Modern Physics, 68 , 13

(1996).

[2] T. O. Wehling, E. Sasioglu, C. Friedrich, A. I. Lichtenstein, M. I. Katsnelson, and S. Blugel,

Phys. Rev. Lett. 106, 236805 (2011).

[3] A. N. Rudenko, F. J. Keil, M. I. Katsnelson, and A. I. Lichtenstein, Phys. Rev. B 88 ,

081405 (2013).

[4] H. Park, K. Haule and G. Kotliar, Phys. Rev. Let. 101 , 186403 (2008).

[5] S. Brener, H. Hafermann, A.N. Rubtsov, M.I. Katsnelson and A.I. Lichtenstein, Physical

Review B, 77 , 195105 (2008).



–56–

LATTICE DYNAMICS IN COPPER CHLORIDE CuCl2

Jane Komleva1*, Sergey Nikolaev1, Alexander Tsirlin2, Vladimir G.Mazurenko1

1 Ural Federal University, Yekaterinburg, Russia

2 Experimental Physics vl, EKM, University of Augsburg, Germany

Copper chloride CuCl2 is an example of the compound with a spin spiral magnetic order

driven by two types of spin-exchange interactions. Moreover, ferroelectricity has been observed

in this system below the Neel temperature TN=23,9 K [1]. It causes possibility of multiferroic

behavior of the compound and implies the presence of phonon instabilities in the magnetically

ordered state. Therefore, lattice dynamics for different magnetic configurations should be

examined.

We computed phonon spectra and thermodynamical properties of CuCl2 using VASP

program package [2] for ferromagnetic (FM) and energetically most favorable collinear

antiferromagnetic (AFM) ordering. These data were obtained in the Phonopy program using a

“frozen phonons” method without consideration of Coulomb interaction (U = 0.0 eV) and with

nonzero value of this parameter, as typical for cupric compounds (U = 7.0 eV).

By analyzing phonon dispersion curves (Fig. 1) for both spin configurations and both values

of the U parameter, we found imaginary phonon frequencies in the FM state. The AFM4 spin

configuration results in a stable crystal structure with minor negative frequencies caused by

numerical effects.

Fig. 1 Phonon dispersions for the FM configuration (U=0.0 eV)

[1] M. Banks, R. Kremer, C. Hoch, A. Simon, Phys. Rev. B, 80, 024404 (2009)

[2] G. Kresse, J. Hafner, Phys. Rev. B, 47, 558 (1993).



–57–

SPIN-ORBIT COUPLING EFFECTS IN ADATOM SYSTEMS

Si(111):{C,Si,Sn,Pb}

Danis Badrtdinov*, Sergey Nikolaev and Vladimir Mazurenko

Ural Federal University, Ekaterinburg, Russia

The adatom systems Si(111):{C,Si,Sn,Pb} are in the focus of modern condensed matter

physics, since they demonstrate a remarkable variety of interesting physical properties such as

charge density wave states [1], isostructural metal-insulator transition [2] and others. As for

magnetic state, it was revealed the formation of the row-wise antiferromagnetic ground state in

Si(111):Sn system confirmed by ARPES experiment [3]. However, all these theoretical

investigations do not take into account the spin-orbit coupling effect, which plays significant

role in formation of magnetic order.

In our work we performed first-principle calculations, where spin-orbit coupling effect was

taken into account. On this basis the Wannier functions were constructed in spinor

representation which describe separated half-filled band near the Fermi level (Fig.1). Hopping

matrices on this basis have non-diagonal components indicating the existence of anisotropic

exchange interactions. In terms of Moriya's superexchange theory, Dzyaloshinskii-Moriya

vectors were estimated, which revealed to be orthogonal to corresponding radius vectors of their

bonds. These anisotropic exchange interactions should be taken into consideration in order to

describe the realistic magnetic state in these systems.

Fig. 1 Left - adatom system Si(111):Sn with Wannier function distribution. Right - band

splittings due to spin-orbit coupling effects.

[1] Carpinelli JM et al, Phys. Rev. Lett. 1997; 79:15.

[2] Hansmann P et al, Phys. Rev. Lett. 2013; 110:166401.

[3] Li G, Hopfner P, Schafer J et al, Nature Comm. 2013; 4:1620.



–58–

LEAD OXYHALIDES Pb3X2O2 (X=Cl, Br, I): AB INITIO CALCULATIONS

OF PHONON SPECTRA AND OPTICAL PROPERTIES

Dmitry Zakir’yanov 1*, Vladimir Chernyshev 1

1 Ural Federal University, Ekaterinburg, Russia

Lead oxyhalides Pb3X2O2 (X=Cl, Br, I) are interesting as a materials with scpecific optic and

ion-cunduction properties [1–3].

Ab initio calculations of the crystal structure and the phonon spectrum of Pb3O2X2 (X=Cl,

Br, I) were performed in the framework of the density functional theory using PBE0 [4]

functional. The CRYSTAL code, designed for periodic systems, was used. A good agreement

with the experimental data has been reached [5]. The results of calculations have made it

possible to interpret the experimental vibration spectra and reveal silent modes, which do not

manifest themselves in these spectra but influence the optical properties of the crystal.

Interpretation of phonon spectra was performed.

Components of the dielectric tensor, birefringence, angle between optic axes and range of

thermodynamic parameters were calculated. In particular, the calculations results shown that the

anisotropy of Pb3O2Br2 will be less pronounced than of Pb3O2Cl2.

Changes in the physical properties of crystals in a sequence Pb3O2Cl2 → Pb3O2Br2 →

Pb3O2I2 were studied by ab initio calculations.

This work was supported by the Russian Foundation for Basic Research, project no. 15-03-

00368a.

[1] Sigman MB, Korgel BA. J. Am. Chem. Soc. 2005; 127:10089.

[2] Siidra OI, Krivovichev SV, Depmeier W. Phys. Chem. 2007; 414:501.

[3] Withers NJ, Akins BA, Rivera AC, Plumley JB, Smolyakov GA, Osinski M. SPIE

Proceedings 2009; 73041N:1.

[4] Perdew JP, Ernzerhof M, Burke K.J. Chem. Phys. 1996; 105:9982.

[5] Zakir’yanov DO, Chernyshev VA, Zakir’yanova ID. Physics of the Solid State 2016;

58:325.



–59–

THE KOHN ANOMALIES IN THREE-DIMENSIONAL SYSTEMS

A. Stepanenko1*, D. Vesnina1, P. Igoshev2,1, A. Katanin2,1

1Ural Federal University, 620002, Ekaterinburg, Russia


The model approaches to itinerant systems allow explaining experimental data and predicting

properties of new materials. These approaches highlight essential peculiarities of the electronic

spectrum, such as van Hove singularities [1] and Kohn anomalies [2,3], which play important

role in physical properties of itinerant systems. While the van Hove singularities lead to

ferromagnetism, Kohn anomalies are important for systems with the spin density wave order.

In this study we investigate a possibility of Kohn anomalies, which are accompanied by a

maximum of the non-uniform magnetic susceptibility at the wave vector 2kF, in systems with

face centered cubic (fcc) and body-centered cubic (bcc) lattice. While the fcc lattice yields such

Kohn anomalies already within the one band model with nearest-neighbor hopping, the bcc

lattice does not possess this property. At the same time, including more distant neighbors and/or

several (at least two) bands yields Kohn anomalies within relatively simple itinerant models on

bcc lattice.

As an example, we consider the model of the two relevant bands of chromium including

hopping between first, second and third neighbors. The fit of the Fermi surfaces was used to

determine Kohn points and study the effect of magnetic correlations within the model approach.

The momentum dependence of magnetic susceptibility at the the non-zero and zero temperature

in the paramagnetic phase is calculated.

Fig. 1 The Fermi surfaces of Cr in the two band model.

[1] van Hove L. Phys. Rev. 1953; 89: 1189.

[2] Kohn W. Phys. Rev. Lett. 1959; 2:393; Rice TM. Phys. Rev. B 1970; 2:9.

[3] Schäfer T, Katanin AA, Held K, Toschi A. arXiv:1605.06355.



–60–

ELECTRON TRANSPORT THROUGH DOUBLE QUANTUM DOTS: THE

FUNCTIONAL RENORMALIZATION GROUP APPROACH

Vladimir Protsenko*, Andrey Katanin

Institute of Metal Physics Ural Branch RAS, Russia

Ural Federal University, Ekaterinburg, Russia

To date, the functional renormalization group approach (fRG) is one of the most promising

methods to study the influence of electron–electron correlations on the transport properties of

quantum dot systems [1, 2]. However, considering the conductance at low magnetic fields of a

system of parallel quantum dots, that connected to common leads, it was found [2] that fRG

approach with the sharp cutoff scheme yields an artificially low conductance when the system is

close to half-filling and the singular Fermi-liquid (FL) state is realized [3].

To describe the conductance in the singular FL regime we propose a new scheme based on

using a counterterm technique within fRG approach. To this end, we choose the 𝛬-dependent

propagator of the quantum dots �̅�𝜎0(𝛬) in the form:

�̅�𝜎0(𝛬) = {[𝐺𝜎

0(𝛬)]−1 + 𝜎𝜒𝛬

2}. (1)

The additional term

𝜎𝜒𝛬

2 = 𝜎

𝐻𝑐

2 {

1, 𝛬 > 𝛬𝑐

𝛬/𝛬𝑐 , 𝛬 > 𝛬𝑐 (2)

allows to start the fRG flow at the finite magnetic field 𝐻𝑐. The magnetic 𝐻 field dependences of

the conductance at the half-filling, calculated in the different approaches are plotted in Fig. 1.

One can see that using the counterterm technique (solid red lower line) eliminates the

unphysical behavior of the conductance, which takes place in the standard fRG approaches at

low magnetic fields (dashed green line and dashed-dotted blue line). The conductance shows the

correct behavior with decreasing of the magnetic field. And significantly improved agreement

with the numerical renormalization group (NRG) data (solid black upper line) is obtained.

Fig. 1 Conductance as a function of magnetic field for U/Γ=1.

[1] Andergassen S., Enss T., Meden V. Phys Rev B 2006; 73: 153308.

[2] Karrasch C., Enss T., Meden V. Phys Rev B 2006; 73: 235337.

[3] Mravlje J. et al. Phys. Rev. Lett. 2012; 108: 066602.



–61–

PLASMONS AND SCREENING IN PHOSPHORUS: BEYOND

WAVELENGTH LIMIT

Danil Prishchenko 1*, Alexander Rudenko 2, Vladimir Mazurenko 1, Mikhail Katsnelson 2


2 Radboud University, Netherlands

Two-dimensional black phosphorus is a promising candidate for usage in modern

technological devices - from gas sensors to field-effect transistors. It has unique characteristics,

such as dependence of band gap on the number of layers and high anisotropy of electronic

properties [1]. Ability to tune band gap by modifying number of layers brought much attention

to this material from the researcher’s side.

We study plasmonics in single and multilayered black phosphorus with inclusion of all

microscopic effects. Using random phase approximation for dielectric function, we were able to

find three different type of plasmonic excitations - intra-band, inter-band and plasmon-like (Fig.

1). The latter two were not visible in long wavelength limit calculations.

New types of plasmonic excitations are promising for technological applications, as they

would allow experimental detection of number of layers and spatial orientation of black

phosphorus.

Fig. 1 Loss function spectrum of mono-, bi- and trilayered black phosphorus. Left sides of

spectra corresponds to the armchair direction, right side - to the zigzag direction.

[1] J. Qiao. Nat. Commun. 2015; 5:4475.



–62–

CONTACTS OF CARBON AND GOLD NANOTUBES:

FIRST PRINCIPLES CALCULATIONS

Sergey Sozykin 1*, Valery Beskachko 1

1 South Ural State University, Chelyabinsk, Russia

Expectations to create a new generation of electronic devices having very small dimensions,

associated with carbon nanotubes (CNT). One of the potential problems that prevent the

implementation of such devices is the high resistance of the CNT-metal contact. Experimental

studies of a number of metals for ohmic contacts lead to contradictory conclusions because of

the difficulty of experimental conditions reproduction. It is thought that the most promising

materials for the contacts are Pd, Ti, Au and Pt. There are also theoretical studies of CNT-metal

contacts. However, they rarely relate to the current-voltage characteristics. In particular, these

characteristics have not been studied for the «end» contact geometry where metal electrodes are

attached to the ends of the tube. Doped metal tube edges are often considered as electrodes.

By now nanotubes obtained not only from carbon, but also from many other elements and

compounds, in particular from noble metals, including the mentioned above (Au, Pt, Pd). Unlike

carbon nanotubes, all metal tubes are conductors and often regarded as wires in nanodevices. It

is interesting to consider how such tubes will act as «end» electrodes. The answer to this

question we have tried to obtain by means of computer simulation.

It is convenient for simulation that the diameters of the CNT and noble metal tubes can be

chosen close. Thus, a CNT (7,7) diameter is close to the diameter of a gold nanotube (10,0). In

our calculations we used models of these nanotubes of 112 and 40 atoms, respectively. The

simulation was performed using the density functional theory and non-equilibrium Green's

functions as implemented in the SIESTA package. We used the exchange-correlation functional

PBE and DZP basis set.

We have determined the equilibrium geometry of the system and electrical charges on atoms

near the C-Au boundary, mechanical strength of the contact and the current-voltage

characteristic of the system.

a b c d

Fig. 1 Atomic structure of (7,7) carbon (a,b) and (10,0) gold (c,d) nanotubes



–63–

THERMODYNAMIC MODELING OF THERMAL DISSOCIATION OF

THE INTERMETALLIC COMPOUNDS PbBi2Sn2

Irina Tikina 1, Nicholas Barbin 1,2*

1 Ural Institute of state fire service of EMERCOM of Russia, Russia

2 Ural state agrarian University, Russia

In the alloy of Bi-Pb-Sn intermetallic compound is formed PbB2Sn2 [1]. Made computer

experiment in the software package TERRA for studying the behaviour of PbBi2Sn2

intermetallic compound by heating in an inert atmosphere with the possibility of formation of

intermetallics BiPb, SnBi, PbSn, Bi2Sn3, Bi5Pb3, Bi7Pb3, Bi7Pb, Pb3Bi4, Pb3Bi, PbSn3, Sn2Bi4,

Sn3Bi, Sn4Bi2, Sn5Bi, Sn10Bi3, SnBi5. Balance charts at atmospheric pressure is shown in Fig. 1

When heated, the intermetallic compound decomposes into metallic Bi(s), Pb(s), Sn(s),

SnBi(s), PbSn(s), BiPb(s) with the evaporation of Bi, Pb, Sn, Bi2. The evaporation of Pb and Bi

occurs at 1100 K, when Sn 1700К.

Fig. 1 Balance charts Sn, Bi, Pb

[1] I. V. Ovchinnikova J. Melts No. 5, 2011, pp. 83-91



–64–

MAGNETIC ANISOTOPY EFFECTS IN FE-GA ALLOYS

Petrik Mikhail 1,2*, Danis Badrtdinov 3


2Institute of quantum materials science, Russia 3 Ural Federal University, Russia

The Fe-Ga alloy attract significant attention since of its abnormally high magnetostriction

[1]. At concentrations of Ga below 19% it appears due to the effect of single Ga atoms in Fe

matrix [2]; at higher concentrations the short-range order plays important role [3]. In order to

obtain the realistic picture of this phenomena on the microscopic level and estimate

magnetostriction by the formula:

)2

/2(3

)/(2

100

dtot

Ed

dMCA

dE

,

(1)

the calculation of the magnetocrystalline anisotropy energy EMCA is necessary. On the basis of

ab initio calculations performed using VASP, the electronic structure of Fe-Ga alloy was

obtained and localized Wannier functions were constructed. These Wannier functions provide

accurate description of the energy spectrum of the system in a wide range of energies. The

Green's functions were constructed from hopping matrices in the basis of Wannier functions

and, considering the weak spin-orbital coupling in this system, the perturbation theory methods

were utilized for the estimation of magnetocrystalline anisotropy energy [4]. This approach can

be considered as very useful for describing magnetoelastic properties of systems with small

MAEs.

A.E. Clark, J.B. Restorff, M. Wun-Fogle , T.A. Lograsso, D.L. Schlagel // IEEE Trans.

Magn. — 2000. —Vol. 36, No. 5 — P. 3238–3240

R. Wu // Journal of Applied Physics. — 2002. — Vol. 91. — P. 7358.

M.V.Petrik, O.I.Gorbatov, Yu.N.Gornostyrev // JETP Letters. — 2014. — V. 98. — P.

809—812.

I. V. Solovyev, P. H. Dederichs, I. Mertig // Physical Review B. – 2011. — Vol. 52, No. 18.

— P. 13419.



–65–

STRUCTURE AND LATTICE DYNAMICS OF BiMnO3: AB INITIO

CALCULATIONS

D. Nazipov1*, A. Nikiforov1, L. Gonchar1,2

1Ural Federal University, Ekaterinburg, Russia 2Ural State University of Railway Transport, Ekaterinburg, Russia

Multiferroics are actively studied and have a wide practical application. The effect of

ferroelectricity and at the same time long-range magnetic order in multiferroic opens the

possibility of creation of electronic devices with controllable magnetic characteristics. At the

present time being searched for multiferoics combining magnetic and ferroelectric properties.

Among the materials, perovskite-like BiMnO3 has attracted particular attention of researchers.

Complicated orbital structure [1,2] on Mn3+ ions leads to ferromagnetic ordering below

Tc=100K and existence of lone pair of 6s2 electrons of Bi3+ may lead to ferroelectric effect.

Thus, a detailed analysis of the microscopic mechanisms of interaction between the magnetic

and crystal subsystems is required.

In this paper we present the results of ab initio calculations of the crystal structure

parameters and the phonon spectrum of BiMnO3. Lattice constants, coordinates of ions in cell

and bond lengths have been obtained for the ferromagnetic C2/с phase in a good agreement with

experiment [3]. Calculated frequencies and intensities of the active modes in IR and Raman

spectra have been compared with the experiment [4].

Calculations have been performed in solid state calculations package CRYSTAL14 [5] in the

framework of MO LCAO approximation, using density functional theory method with hybrid

DFT/HF functionals. The ions are described by full-electron Gauss-type basis sets and

pseudopotential for Bi3+.

In model approach orbital ordering and splitting of 5D (3d4) term of two nonequivalent Mn3+

ions have been obtained using crystal field approximation.

A.M. dos Santos, A.K. Cheetham, T. Atou, Y. Syono, Y. Yamaguchi, K. Ohoyama, H.

Chiba, C.N.R. Rao. Phys. Rev. B 66, 064425 (2002).

L.E. Gonchar, A.E. Nikiforov. Phys. Rev. B 88, 094401 (2013).

A.A. Belik, S. Likubo, T. Yokosawa, K. Kodama, N. Igawa, S. Shamoto, M. Azuma, M.

Takano, K. Kimoto, Y. Matsui, E. Takayama-Muromachi. J. Am. Chem. Soc. 129, 971

(2007).

W. S. Mohamed, A. Nucara, G. Calestani, F. Mezzadri, E. Gilioli, F. Capitani, P. Postorino,

P. Calvani. Phys. Rev. B 92, 054306 (2015).

URL: http://www.crystal.unito.it/index.php



–66–

STRUCTURE AND LATTICE DYNAMICS OF PrFe3(BO3)4:

AB INITIO CALCULATION

Vladimir Chernyshev1*, Anatoliy Nikiforov 1, Vladislav Petrov 1


The crystal structure and phonon spectrum of PrFe3(BO3)4 are ab initio calculated in the

context of the density functional theory [1,2]. The ion coordinates in the unit cell of a crystal and

the lattice parameters are evaluated from the calculations. The types and frequencies of the

fundamental vibrations, as well as the line intensities of the IR spectrum, are determined. The

elastic constants of the crystal are calculated. A “seed” frequency of the vibration strongly

interacting with the electron excitation on the praseodymium ion is obtained for low-frequency

A2 mode. The calculated results are in agreement with the known experimental data.

[1] Tsirel’son V. G., Quantum Chemistry: Molecules, Molecular Systems and Solids, Moscow:

Binom; 2010 [in Russian].

[2] Dovesi R., Saunders V. R., Roetti C., Orlando R., Zicovich-Wilson C. M., Pascale F.,

Civalleri B., Doll K., Harrison N. M., Bush I. J., D’Arco Ph., Llunell M., CRYSTAL09

User’s Manual (University of Torino, Torino, Italy, 2009).

http://www.crystal.unito.it/index.php, 2009.



–67–

LANTHANIDE-DOPED GERMANATES: DFT STUDY OF LATTICE

DYNAMICS AND ELECTRONIC STRUCTURE OF OPTICAL HOSTS

Ivan Leonidov 1*, Vladislav Petrov 2, Vladimir Chernyshev 2,

Alexey Ishchenko 2, Ekaterina Konstantinova 1, Anatoliy Nikiforov 2

1 Institute of Solid State Chemistry Ural Branch RAS, Russia


Multifunctional materials based on the M2Ge7O16 (M = Ca, Cd), CaY2Ge4O12, CaLa2Ge3O10

germanates are of considerable interest for their applications in solid state electrochemistry and

optical engineering [1, 2]. While these compounds doped with lanthanide ions have been

extensively studied by different experimental techniques, DFT-aided interpretation of their

crystal structures and physical/chemical properties has been discussed in few recent papers [3,

4].

A series of DFT functionals has been applied in describing the equilibrium crystal structure,

FTIR and Raman spectra, and electronic properties of Ca2Ge7O16, CaY2Ge4O12, CaLa2Ge3O10.

Calculations have been performed with the periodic ab initio CRYSTAL code using all electron

Gaussian-type basis sets. The following exchange-correlation functionals have been tested: LDA

functional (SVWN), semilocal GGA tailored for molecules (PBE), the functionals devised for

solids (PBEsol, WC), and several hybrids (B3LYP, WC1LYP, PBE0, PBE(n = 6)). Whereas

GGA functionals reproduce quite well the crystal structure, they fail for the phonon spectra and

electronic structure of the studied oxides. The inclusion of HF exchange in the hybrid

functionals leads to very good predicted structures of the germanates of different types. The

most accurate geometry description and optical band gap estimation, and the best agreement

between the recorded infrared and Raman spectra and their computed counterparts have obtained

with the WC1LYP and PBE (n = 6) hybrid functionals.

This work was partially supported by the RFBR Grant No. 14–03–31324. Computational

procedures were carried out at the URAN Computing Platform at IMM UB RAS (Ekaterinburg,

Russia). I. L. would like to acknowledge support from the Russian President Fellowship SP–

931.2016.1.

Aravindan V, Lee YS, Madhavi S. Adv Energy Mater 2015; 5:1402225.

Leonidov II, Zubkov VG, Tyutyunnik AP, Tarakina NV, Surat LL, Koryakova OV,

Vovkotrub EG. J Alloys Compd 2011; 509:1339.

Leonidov II, Petrov VP, Chernyshev VA, Nikiforov AE, Vovkotrub EG, Tyutyunnik AP,

Zubkov VG. J Phys Chem C 2014; 118:8090.

Wang T, Gou J, Xu XH, Zhou DC, Qiu JB, Yu X. Opt Express 2015; 23:12595.



–68–

ELECTRONIC STRUCTURE AND MAGNETIC PROPERTIES OF THE

STRONG-RUNG SPIN-1 LADDER Rb3Ni2(NO3)7

ZlataV. Pchelkina1,2*, O. S. Volkova2,3, V. V. Mazurenko2, A. N. Vasiliev2,3,4

1 M.N. Miheev Institute of Metal Physics of Ural Branch of RAS, Ekaterinburg, Russia 2Department of Theoretical Physics and Applied Mathematics, Ural Federal University,

Ekaterinburg, Russia 3 Lomonosov Moscow State University, Moscow, Russia

4National University of Science and Technology “MISiS,” Moscow, Russia

The electronic structure and magnetic properties of Rb3Ni2(NO3)7, the prototype material of

the strong-rung spin-1 ladder model, was calculated within LDA+U approximation. The

isotropic exchange, Dzyaloshinskii-Moriya interactions and single-ion anisotropy tensor were

calculated by using the magnetic force theorem with different types of perturbations [1, 2]. The

analysis of partial orbital contributions into the matrix of exchange integrals reveals the reason

of strong exchange along the rungs of the ladder. The Heisenberg model with obtained

interatomic exchange interactions was solved by quantum Monte Carlo method. The model

magnetization and spin susceptibility, as well as theoretical estimation of the Curie-Weiss

temperature are in good agreement with the experimental one. The several plateaus in the filed

dependence of magnetization at low temperatures are predicted.

[1] Lichtenstein A I, Katsnelson M I, Antropov V P, and Gubanov V A, J. Magn Magn Mater

1987; 67:65.

[2] Mazurenko V V and Anisimov V I, Phys Rev B 2005; 71:184434.



–69–

FULL POTENTIAL STUDY OF ELECTRONIC AND MAGNETIC

PROPERTIES OF FUNCTIONALISED GRAPHENE.

Ilya Piterskikh 1*, Danil Boukhvalov 1,2, Vladimir Mazurenko 1

1 Institute of Physics and Technology, Ural Federal University, Ekaterinburg, Russia

2 Department of Chemistry, Hanyang University, Seoul, Republic of Korea

Numerous studies have shown high sensitivity of graphene electron and its energy structure

to defects of various kinds, including the atoms adsorbed on its surface, thus confirming that the

chemical modification of graphene is a promising direction of the management of its electronic

structure. Due to the fact that a significant portion of the above studies made on the basis of the

pseudopotential method, it is of interest to study the changes in the electronic structure of

graphene with the density functional theory (DFT) on the basis of the full-potential wave

function using linearized augmented plane wave method (FP-LAPW). Research was conducted

with Wien2k package, exchange and correlation energies were evaluated with the local density

approximation (LDA).

The results of changes in the electronic structure and magnetic properties of graphene at

various numbers of adsorbed atoms of hydrogen and fluorine were presented. It is found that the

magnetic properties of graphane and fluorographene depend on the distance between adjacent

atoms adsorbed, and the distance between the fluorine atom and its associated carbon atom in

the lattice of graphene. The features of the band structure and the electron density as a function

of fluorine concentration and the degree of deformation of the graphene planes during the

adsorption of fluorine were studied. The effect of the concentration of adsorbed fluorine as a

factor of mutual influence of interaction between neighboring fluorine atoms on the electron

graphene structure (C2F, C4F and C18F) was shown.

It is shown that the magnetic properties of graphane and fluorographene depend on the

distance between adjacent atoms adsorbed, and the distance between the fluorine atom and its

associated carbon atom in the graphene lattice.

[1] http://www.wien2k.at/

[2] Rudenko A.N. et al. Phys. Rev. B. 88, 081405 (2013)

[3] Fabian J. et al. Physical Review B (PRB) 91, 115141 (2015)

[4] Boukhvalov D. et al. J Phys Cond Matter 2009; 21(34):344205.Manning JR. Diffusion

kinetics for atoms in crystals, London: Van Nostrand; 1968.



–70–

STRUCTURAL, ELECTRONIC PROPERTIES, STABILITY AND FERMI

SURFACES OF TERNARY BORIDES CaM2B2, CaM3B2, Ca2M5B4,

Ca3M8B6 (M = Rh, Ir)

Dmitrii Suetin 1*

1 Institute of Solid State Chemistry, Ural Branch RAS, Russia

In the context of the importance of finding new superconductors a significant interest on

recent discovery of superconductivity in ternary boride Ca3Rh8B6 with TC = 4 K [1] take place.

This boride includes in the homologous series AM3n-1B2n (A = Ca, Sr; M = Rh, Ir), n = 1, 2, 3,

which members have an orthorhombic structure. In addition to these phases, in ternary Ca-M-B

system, it is known about the existence of CaM3B2 (M = Rh, Ir) borides with hexagonal crystal

structure.

For the first time we have studied the main features of structural, electronic properties, phase

stability and Fermi surface topology of eight Ca containing ternary borides CaM2B2, CaM3B2,

Ca2M5B4, Ca3M8B6 (M = Rh, Ir) within FLAPW-GGA method realized in WIEN2k code [2].

We calculate the formation energies (Eform) of the borides based on the following reactions

such as Ca + 2M + α-B → CaM2B2. It is found that all values Eform <0 and are comparable with

each other, i.e. all borides are energetically stable with respect to mechanical mixture of Ca, M,

and α-B, see Table 1. In addition, Ir borides are more stable compared to Rh borides.

A characteristic feature of the electronic spectra for CaM2B2, CaM3B2, Ca2M5B4 and

Ca3M8B6 (M = Rh, Ir) is the presence of two main regions with different partial composition.

Fermi level crosses low-dispersion bands having predominantly M d nature and determining the

metallic properties of borides. Thus for CaM2B2, CaM3B2 near-Fermi region falls to the bottom

of the density of states, while for Ca2M5B4 and Ca3M8B6 the density of electronic states at the

Fermi level N(EF) significantly increases.

Table 1. The formation energies relatively to Ca, M and α-B (Eform, in eV/atom) for ternary

borides CaM2B2, CaM3B2, Ca2M5B4 и Ca3M8B6 (M=Rh, Ir).

boride CaRh2B2 CaRh3B2 Ca2Rh5B4 Ca3Rh8B6

Eform -0.817 -0.881 -0.856 -0.874

boride CaIr2B2 CaIr3B2 Ca2Ir5B4 Ca3Ir8B6

Eform -0.956 -0.917 -0.939 -0.942

[1] Takeya H, ElMassalami M, Terrasoz LA, Rapp RE, Capaz RB, Fujii H, Takano Y, Doerr M,

Granovsky SA. Sci. Techn. Adv. Mater. 2013; 14:035003.

[2] Blaha P, Schwarz K, Madsen GKH, Kvasnicka D, Liutz J, WIEN2k, An Augmented Plane

Wave Plus Local Orbitals Program for Calculating Crystal Properties, Vienna: Vienna

University of Technology, 2001.



–71–

OXYGEN ION DIFFUSIVITY IN SCANDIA-STABILIZED

ZIRCONIA: MOLECULAR DYNAMICS SIMULATIONS AND

AB INITIO CALCULATION

Maria Ivonina*, Pavel Snegurov, Vladimir Sizov

Saint Petersburg State University, Saint Petersburg, Russia

The cubic phase of zirconia (zirconium dioxide, ZrO2) stabilized by oxides of aliovalent

metals displays ionic conductivity caused by the presence of charge-balancing vacancies in the

anionic sub-lattice. Zirconia-based ionic conductors are widely used as electrolytes in solid

oxide fuel cells. In particular, doping of zirconia by scandium oxide (Sc2O3) results in scandia-

stabilized zirconia (ScSZ), which can achieve higher conductivity compared to other commonly

used materials under the same operating conditions [1]. In this work classical molecular

dynamics simulations and ab initio calculations are used to study the mechanisms of oxygen

diffusion in ScSZ.

The dependence of oxygen self-diffusion coefficients on temperature and scandia

concentration was studied by molecular dynamics simulations. The number of vacancies

increases with increasing dopant concentration, providing a wide variety of possible migration

pathways for oxygen ions. These migration pathways were analyzed by monitoring the

trajectories of oxygen ions obtained from molecular dynamics simulations. Investigation of the

dependence of diffusion coefficients on inverse temperature provides information on diffusion

activation energies, which can be used to quantify the energy barriers for diffusion of oxygen

ions.

Nudged elastic band (NEB) method was used as an alternative ab initio approach to evaluate

the energy barriers for various oxygen migration pathways in ScSZ. The results obtained from

ab initio calculations were compared to the data obtained from classical simulations and from

the literature [2–3].

T. H. Etsell, S. N. Flengas, Chem. Rev. 70, 339-376 (1970).

Z. Q. Yu, R. Devanathan, W. Jiang, P. Nachimuthu, V. Shutthanandan, L. Saraf, C. M.

Wang, S. V. N. T. Kuchibhatla, S. Thevuthasan, Solid State Ionics 181, 367–371 (2010).

A. Kushima, B. Yildiz, J. Mater. Chem. 20, 4809–4819 (2010).



–72–

ATOMISTIC SIMULATION OF STACKING FAULTS IN CEMENTITE

Kar’kina L.E.a*, Kar’kin I.N. a,b, Kuznetsov A.R. a,b

aInstitute of Metal Physics UB RAS, Ekaterinburg, Russia,

bInstitute of Quantum Materials Science, Ekaterinburg, Russia

Precipitation of lamellar or globular cementite in ferrite defines high strength of pearlite class

steels. Experimental investigations have established that cementite can be deformed not only at

high temperatures, but also at room temperature. However, the experimental determination of

the slip systems in cementite encounters considerable experimental difficulties. Atomistic

simulation of stacking faults allows us to offer possible and the most energetically favorable

types of full and partial dislocations, which carry out the deformation of cementite.

Molecular dynamics method was used to study γ-surfaces for some planes of cementite

containing Burgers vectors [100] and [010]. Displacement vectors corresponding to stable

stacking faults have been determined. The energy of these stacking faults has been calculated by

the molecular dynamics and ab initio methods. The energy of unstable stacking faults, which

characterizes the tendency of a material to plastic relaxation, has been estimated. The reactions

of the splitting of perfect dislocations have been suggested; the possibility of the propagation of

stacking faults in the planes under consideration is discussed.

The results of crystallographic analysis of deformation transfer mechanisms across the

ferrite/cementite interface in fine lamellar pearlite are presented. Slip planes and Burgers vectors

of full and partial dislocations in cementite have been proposed on the basis of the results of

atomistic simulations of stacking faults for some planes of cementite. It has been found that

strain transfer through the Fe/Fe3C interface is possible only for half of the slip systems

1/2<111>{110}F of ferrite.

The research was carried out within the state assignment of FASO of Russia (themes

“Structure” No. 01201463331 and “Deformation” No. 01201463327). The results have been

obtained using the computational resources of MCC National Research Center “Kurchatov

Institute” (http://computing.kiae.ru) and Uran supercomputer of Institute of mathematics and

mechanics UB RAS.



–73–

THE PRECIPITATION KINETICS AND GPZ FORMATION IN AL-

BASED ALLOYS. MASTER EQUATION APPROACH WITH AB-INITIO

PARAMETERIZATION

Andrey Stroev1,2, O. Gorbatov2, Yuri Gornostyrev1,2

1Institute of Metal Physics Ural Branch RAS, Ekaterinburg, Russia

2Institute of quantum materials science, Ekaterinburg, Russia

AlCu-based alloys still nowadays are of great importance for light-weight and durable

constructions. The hardening of Al is crucially dependent on coherent meta-stable precipitates

formed during aging at room or moderately high temperature. In binary AlCu alloys these

precipitates are thin Cu platelets of a few nanometer thickness on the {100}-planes in fcc-Al;

they are called Guinier-Preston zones (GPZ).

The mixed-space cluster expansion (MSCE) model coupled with Monte Carlo

simulations was proposed in Ref. [1] to describe precipitation of Cu in fcc Al. Here we develop

consistent “flat-space” approach based on the recently developed master equation method [2] for

description of decomposition of binary alloys. In this approach the energy of alloy is presented

in the form of the cluster expansion taking into account as pair as well ternary and quaternary

interaction between solute atoms. Wherein, instead of the anisotropic elastic contribution to

interaction energies, we consider renormalization chemical interactions due to atomic relaxation.

A simple master equation based model with parameterization from ab-initio calculations for Al-

Cu and Al-Mg alloys is presented. Within framework of this approach, the numerical

simulations of alloy decomposition were done and the dependence of precipitates morphology

on temperature/concentration has been investigated. Based on obtained results, conditions of the

GPZ formation have been clarified.

The research was carried out within the state assignment of FASO of Russia (themes

“Structure” No. 01201463331) and under financial support from the Russian Science Foundation

(grant 14-12-00673).

[1] S. Muller, C. Wolverton, L.-W. Wang and A. Zunger, Europhys. Lett., 55, 33 (2001)

[2] K. Yu. Khromov, F. Soisson, A. Yu. Stroev, V. G. Vaks. Solid State Phenomena, 172-174,

1146-1155, (2011).



–74–

DECOMPOSITION KINETICS IN Fe–Cu DILUTE ALLOYS.

MONTE CARLO SIMULATION

Ivan Shmakov1,2, Ilya Razumov1,2, Yuri Gornostyrev1,2


2Institute of quantum materials science, Russia

A significant effect of bcc Cu precipitates on the mechanical characteristics stimulated

numerous studies of the decomposition of supersaturated Fe–Cu based solid solutions using

advanced experimental techniques and theoretical approaches [1]. Here we propose a

generalization of the statistical (Monte Carlo) simulation technique for modeling of the

decomposition kinetics in the Fe–Cu system by taking into account the dependence of the

effective interactions both on the magnetic state of the alloy and on the local concentration of the

dissolved chemical element. Similar approach was early implemented in [2] for the Fe–Cr alloy.

We demonstrate that the concentration dependence of the effective interactions results in

significantly shift the line corresponding to the onset of the transformation in the time–

temperature– transformation (TTT) diagram toward longer times providing better agreement

with the experiment. Thus, the presented results demonstrate that the inclusion of the

concentration dependence of the effective interactions is critically important for the adequate

description of the decomposition kinetics in the alloy [4].

Fig. 1. Calculated TTT diagram of decomposition the dilute Fe–1.2 at %Cu alloy. The curves

correspond to achieving the specified degree of decomposition of 0.10 (curves 1 and 2) and 0.20

(curves 1' and 2') at a fixed temperature. The concentration dependence of the effective

interactions is neglected (curves 1 and 1') and taken into account in curves 2 and 2'. Curve 3

shows the experimental data [3] for a transformation fraction of 10%.

[1] O. I. Gorbatov, I. K. Razumov, Yu. N. Gornostyrev, V. I. Razumovskiy, P. A.

Korzhavyi, and A. V. Ruban, Phys. Rev. B 88, 174113 (2013).

[2] A. V. Ruban, P. A. Korzhavyi, and B. Johansson, Phys. Rev. B 77, 94436 (2008)

[3] M. Perez, F. Perrard, V. Massardier, X. Kleber, A. Deschamps, H. De Monestrol, P.

Pareige, and G. Covarel, Philos. Mag. 85, 2197 (2005)

[4] I.G. Shmakov, I.K. Razumov, O.I. Gorbatov, Yu.N. Gornostyrev, P.A. Korzhavyi,

ZhETP Letters, 103, No. 2, 119 (2016)



–75–

MOLECULAR DYNAMICS SIMULATION OF BULK XENON

DIFFUSION IN UO2: A COMPARISON OF AB INITIO INTERACTION

POTENTIALS

Kirill Nekrasov*, Natalia Kichigina

Department of Technical Physics, Ural Federal University,

620002 Yekaterinburg, Russia

Accumulation of radiogenic xenon in nuclear fuel causes swelling of the material and can

degrade its exploitation characteristics. Transport of xenon atoms in the oxide fuels such as UO2

can be studied using molecular dynamics simulation. A number of sets of ab initio interaction

potentials for the Xe – UO2 system have been suggested, some of them calculated using the

relativistic Hartree-Fock method [1] and other fitted to density functional theory calculations [2–

4]. In this work, the potentials [1–2, 4] are used for molecular dynamics simulation of bulk

migration of single Xe atoms in stoichiometric UO2 nanocrystals with free surface. The diffusion

coefficients and activation energies and mechanisms obtained for the different potential sets are

compared with each other and the existing experimental data. The calculated values of the

diffusion coefficients and energies are in quantitative agreement with the experiment.

[1] Jackson R A and Catlow C R A 1985 J. Nucl. Mater. 127 161.

[2] Geng H Y, Chen Y, Kaneta Y and Kinoshita M 2008 J. Alloys Compounds 457 465.

[3] Chartier A, Van Brutzel L and Freyss M 2010 Phys. Rev. B 81 174111.

[4] Thompson A E, Meredig B and Wolverton C 2014 J. Phys.: Condens. Matter 26 105501.



–76–

SIZE MISFIT VERSUS ELECTRONIC EFFECTS IN DIFFUSION OF

SUBSTITUTIONAL IMPURITIES IN NI MATRIX

Ilya Lomaev1,2*, Dmitry Novikov3, Sergey Okatov1,

Yuri Gornostyrev1,2, Sergey Burlatsky3

1 CJSC Institute of Quantum Materials Science, Yekaterinburg, Russia

2 Institute of Metal Physics UB RAS, Yekaterinburg, Russia 3 United Technologies Research Center (UTRC), USA

Atomic diffusion is one of the key factors controlling phase transformations and

microstructure evolution in materials, especially at high temperatures. Despite the obvious

fundamental and technological importance of diffusion in solids, we still know little about the

microscopic mechanisms and factors that affect it. In the present study we implement a

transition state theory of vacancy mediated diffusion with parameters calculated from first-

principle density-functional theory (DFT) to determine the diffusion coefficients of SP and

transition metal (TM) substitutional impurities in fcc Ni.

According to the traditional point of view, a larger atom has larger migration barrier and

consequently lower diffusion mobility. We demonstrate that this is not the case for diffusion of

TM elements in Ni matrix. The larger atoms indeed produce larger lattice strain. However, this

results firstly in the higher solute–vacancy binding energy. Secondly, the equilibrium position of

impurity becomes shifted towards adjacent vacancy. The larger atoms are shifted strongly, with

their migration barriers being significantly decreased. These two reasons lead to a controversial

at first site consequence — the larger atoms diffuse faster. Nevertheless, this phenomenon still

can be described using size misfit arguments.

Quite different situation is observed in the case of SP impurities. We demonstrate that

diffusivities of SP-impurities in TM-matrix are mainly affected by features of chemical bonding

rather than by atomic size misfit and are well correlated with charge on the impurity atom. As an

example, the sulfur atom has the lowest charge among other SP-impurities and as a result its

diffusion coefficient was found to be at list two orders of magnitude higher than that for others

in good agreement with experimental data. Moreover, sulfur was shown to have very low

migration barrier due to formation of covalent-like bonds between S3p and Ni3d orbitals in

saddle point and destabilization (“softening”) of the surrounding Ni-matrix.

This work was performed according to the State Task of the FANO of the Russian Federation

(theme “Deformation,” no. 01201463327)


AUTHOR INDEX

Andreev Sergey .................................................................................... 8,51

Anisimov Vladimir ......................................................................... 3,16,29

Badrtdinov Danis ............................................................................ 6,9,57,64

Bannikov Vyacheslav ........................................................................... 8,54

Barbin Nikolay...................................................................................... 9,63

Boukhvalov Danil ........................................................................... 6,9,36,69

Chernyshev Vladimir ................................................................ 8,9,58,66,67

Eriksson Olle ........................................................................................ 3,17

Gorbatov Oleg .................................................................................. 6,41,73

Gornostyrev Yuri ...................................................... 10,36,41,45,73,74,76

Gerasimov Arsenii ................................................................................ 7,49

Greshnyakov Vladimir ......................................................................... 7,47

Hickel Tilmann ............................................................................... 5,6,31,33

Ivonina Maria...................................................................................... 10,71

Kashin Iliya ........................................................................................... 8,50

Kardashin Andrey ...................................................................................... 10

Karkina Lydia ....................................................................................... 10,72

Katanin Andrey ........................................................................ 3,8,13,59,60

Katsnelson Mikhail ........................................................................... 9,36,61

Khmelevskyi Sergei .............................................................................. 5,30

Komleva Evgenia.................................................................................. 8,56

Korotin Mikhail ...................................................................................... 5,26

Korzhavyi Pavel...................................................................................... 7,43

Kuznetsov Andrey ................................................................................ 10,72

Leonidov Ivan ......................................................................................... 9,67

Leonov Ivan ...................................................................................... 3,14,29

Lichtenstein Alexander ................................................................... 3,8,12,55

Lomaev Ilya .................................................................................... 10,41,76

Mazurenko Vladimir ............................... 4,7,9,10,25,49-52,55-57,61,68,69

Medvedeva Daria .................................................................................... 8,55

Medvedeva Nadezhda ............................................................................. 6,40

Mirzoev Alexander ................................................................................. 6,39

Morris James ........................................................................................... 7,42

Nazipov Dmitry ...................................................................................... 9,65

Nekrasov Igor ................................................................................. 4,8,19,53

Nekrasov Kirill ..................................................................................... 10,75

Neugebauer Jörg ............................................................................ 5,6,31,33

Oguchi Tamio ......................................................................................... 4,23

Pavlov Nikita .......................................................................................... 8,53

Pchelkina Zlata ....................................................................................... 9,68

Petrik Mikhail ................................................................................. 7,9,45,64

Piterskikh Ilya ......................................................................................... 9,69

Poteryaev Alexander ............................................................................. 5,32

Pourovskii Leonid ................................................................................. 3,18

–78–

Pravednicov Andrey .................................................................................. 10

Prishchenko Danil ............................................................................. 9,10,61

Protsenko Vladimir ............................................................................... 8,60

Razumov Ilya ............................................................................................. 74

Razumovskiy Vsevolod ........................................................................ 6,38

Rohringer Georg ................................................................................... 4,21

Rubtsov Alexey .................................................................................... 4,22

Rudenko Alexander ........................................................................ 6,9,27,61

Savrasov Sergey.................................................................................... 5,35

Sekania Mikheil .................................................................................... 7,44

Shmakov Ivan ..................................................................................... 10,74

Shundalov Maksim ............................................................................... 7,48

Simak Sergey ........................................................................................ 6,37

Skornyakov Sergey ......................................................................... 5,7,29,49

Slobodchikov Anatoliy ......................................................................... 8,53

Solovyev Igor......................................................................... 4,7,8,24,50,51

Sotnikov Oleg ....................................................................................... 8,52

Sozykin Sergey ..................................................................................... 9,62

Stepanenko Andrey ............................................................................... 8,59

Streltsov Sergey .................................................................................... 3,15

Stroev Andrey ..................................................................................... 10,73

Suetin Dmitry........................................................................................ 9,70

Toschi Alessandro ............................................................................ 4,20,21

Tsirlin Alexander ..................................................................... 5,8,10,28,56

Verkhovykh Anastasia .......................................................................... 6,39

Vesnina Daria ....................................................................................... 8,59

Zainullina Veronika ...................................................................................

Zakir’yanov Dmitry .............................................................................. 8,58

–79–

–80–

–81–

–82–

–83–

–84–

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