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First Principles Study on the ElectronicProperties of Ca10(Pt3As8)(Fe2As2)5
Elizabeth HilliardAdvisors: Dr. M. Jarrell and Dr. J. MorenoGraduate Student Advisor: Chinedu Ekuma
Louisiana State University, Center for Computation and Technology,Research Experience for Undergraduates
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Outline
Motivations: Why Ca10(Pt3As8)(Fe2As2)5?
Methods: Density Functional Theory (DFT)
Results: Ground state of Ca10(Pt3As8)(Fe2As2)5
Conclusions and Future Work
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Motivations: Why Ca10(Pt3As8)(Fe2As2)5?
Superconductors
Conduct with zero electrical resistance
Expel magnetic fields
Powerful electromagnets - important for technology
Higher critical temperature of some materials still notunderstood
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Motivations: Why Ca10(Pt3As8)(Fe2As2)5?
New class: Iron-basedHigh-Tc Superconductors
Superconductivity couldhave to do with magneticconfiguration
Some research has beendone, but ground statepreviously unknown
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Methods: Density Functional Theory (DFT)
DFT is a first-principle ab-initiomethod utilized in obtaining theproperties of materials
WIEN2k is an all-electron code withproven high accuracy.
For these calculations, we ranWIEN2k on the LONIsupercomputer QueenBee
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Results: Ca10(Pt3As8)(Fe2As2)5Ground State Energy Calculation
Calculations were run for each of three magneticconfigurations: nonmagnetic, ferromagnetic, andantiferromagnetic
Lowest energy configuration: Antiferromagnetic
Difference between antiferromagnetic energy and nextlevel up, ferromagnetic, is 0.677 eV/Fe
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Results: Ca10(Pt3As8)(Fe2As2)5Density of States (DOS)
Comparison of the DOS forthe nonmagnetic (NM),ferromagnetic (FM), andantiferromagnetic (AFM)configurations.
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Results: Ca10(Pt3As8)(Fe2As2)5Electronic Band Structure
The calculated electronic bandstructure in the antiferromagneticconfiguration.
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Conclusions and Future Work
Antiferromagnetic ground state, followed by theferromagnetic phase
Importance: Doped cases can now be researched moreeffectively
Fe-based superconductors could help us understand howsuperconductors come about
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Acknowledgements
Thanks to Dr. Juana Moreno, Dr. Mark Jarrell, andChinedu Ekuma for advising me this summer
This work is supported by the National ScienceFoundation (NSF) Award No. LA-SiGMA EPS-1003897with additional support from the Center for Computationand Technology at Louisiana State University
This material is based upon work supported by theLouisiana Optical Network Institute (LONI).
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Questions?
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References
P. Blaha, K. Schwarz, G. K. H. Madsen, D. Kvasnickaand J. Luitz, WIEN2k, An Augmented Plane Wave +Local Orbitals Program for Calculating Crystal Properties(Karlheinz Schwarz, Techn. Universitat Wien, Austria),2001. ISBN 3-9501031-1-2
N. Ni, J. M. Allred, B. C. Chan, and R. J. Cava, PNAS.108, E1019 (2011).
M. Neupane, C. Liu,et all arXiv 1110.4687v1, (2011