time and spin resolved pes - stanford university · 2012. 3. 5. · fls 2010 icfa beam dynamics...
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FLS 2010 ICFA Beam Dynamics Workshop SLAC March 1-5, 2010
Time and Spin Resolved PES
Fulvio ParmigianiDepartment of Physics, University of Trieste
and FERMI@elettra
FLS 2010 ICFA Beam Dynamics Workshop SLAC March 1-5, 2010
The study of the electron dynamics relays on the ability to time-resolve the ultra-rapid scattering processes which result in energy and momentum relaxation,recombination and diffusion.
In typical experiments a short-pulsed (10-100 fs) laser can be used forphotoemission experiments in the time-domain, whereas longer laser pulses (1-5ps) provided by FT limited coherent sources can be used for photoemissionexperiments in the frequency (energy) domain with unrecorded resolving power.
Experimental techniques must be brought to bear in which band-structurespecificity are combined with time resolution. Angle resolved photoemission isparticularly suited for such experiments.
FLS 2010 ICFA Beam Dynamics Workshop SLAC March 1-5, 2010
Kinetic
Energy
θ
φ
UltrahighVacuum
θinc
A few new directions in photoemission measurements
Core-levels I(θ,φ)
Photo-e- diff./holog.
BindingEnergyBindingEnergy
Emission angle→k
Valence-levels
yx z
Energy
Up to 10 keV
Space &Time Resol.
Next gen. detector & Low-T sample goniometer
+ Other spectroscopies:XES, XAS,…
NiO(001)
W(110)
Curtesy C. Fadley, UC Davis & ALS
FLS 2010 ICFA Beam Dynamics Workshop SLAC March 1-5, 2010
The 10-18 s Challenge with 0.1-1 keV soft X-ray
Nature Physics, June 2007
FLS 2010 ICFA Beam Dynamics Workshop SLAC March 1-5, 2010
Cluster and nanopar ticle spectroscopySpokespersons: F. Stienkemeier, (Univ. of Freiburg-D); T. Moeller (Frei University, Berlin)Co-proponents :K.Fauth (MPI- Stuttgart, D), M. Drabbels (EPFL- CH), M. Schmidt(CNRS –Orsay, Fr), U.Buck (MPI-Goettingen, D)
LDM
Carlo Callegari: LDM coordinatorF. Stienkemeir: End station spoke person
COHERENCE+TUNABILITY+POLARIZATION
FLS 2010 ICFA Beam Dynamics Workshop SLAC March 1-5, 2010
Y. L. Chen, W.S. Lee and ZX. Shen- PNAS 106, 963 (2009)
FLS 2010 ICFA Beam Dynamics Workshop SLAC March 1-5, 2010
FLS 2010 ICFA Beam Dynamics Workshop SLAC March 1-5, 2010
HTSCs
Selective excitations (CT and phonons) to study transient states and photo-induced phase transitions.Superconductors (e-ph interactions, magnetism and superconductivity).Magnetic materials (dynamics of the magnetic excitations).Strong correlations in hard- and soft- condensed matter (charge transfer and phonon assisted excitations).
?
LaBaCuO4
sp-band BCS SC- MgB2
doped-C60
IntercalatedGraphite
e-ph
FLS 2010 ICFA Beam Dynamics Workshop SLAC March 1-5, 2010
fcc-fcc isostructural transition:1.15% volume collapse
cell-length : 5.1612 4.677cell-volume : 137.4 102.3symmetry: F m -3 m
2.Curie Weiss magnetism-Pauli Magnetism (zero moment)
alpha-gamma phase transition in cerium:•Promotional Model ?•Mott transition ?•Kondo Volume Collapse ?
Dynamics of the volume collapse
Light induced shock-wave
FLS 2010 ICFA Beam Dynamics Workshop SLAC March 1-5, 2010
Photoelectron SpectroscopyC1s, O1s and
Pt4f XPS
CO adsorption
Fermi surface of BSCCO measured by ARPES. The experimental data shown as an intensity plot in yellow-red-black scale. Green dashed rectagle represents the Brillouin zone of the CuO2 plane of BSCCO.
FLS 2010 ICFA Beam Dynamics Workshop SLAC March 1-5, 2010
101 102 1030
10
20
30
40
IMFP
(A)
E-EF-φ (eV)
full Penn model single pole Penn
Al
101 102 1030
10
20
30
40
full Penn model single pole Penn
Si
IMFP
(A)
E-EF-φ (eV)
101 102 1030
10
20
30
40
full Penn model single pole Penn
Cu
IMFP
(A)
E-EF-φ (eV)
S.F. Mao and Z.J. Ding, Hefei (TBP)
More realistic look at low-energy inelastic
mean free paths--theory
FLS 2010 ICFA Beam Dynamics Workshop SLAC March 1-5, 2010
Team:
INFM-Lab. TASCELETTRA
Univ. Rome III,EPFL LURE
ESRF (ID16)0.3 0.2 0.1 0.0 -0.1 -0.2 -0.30
50
100
150
200
250
Exp. Fit
Inte
nsity
(Cou
nts)
Binding Energy (eV)
Au Fermi edgeT = 20Khν = 5933eV EP= 20 eV, slit 0.4 mm∆Eexp = 71 meV
VOLPE project: VOLume PhotoEmission with Synchotron Radiation
Panaccione et al. NIMA (2005)Torelli et al., Rev.Sci. Instr. 76, 023909 (2005)
71 meV @ 5933 eV50 meV analyser
High Resolution /High Flux beamline: ID16 @ ESRF
FLS 2010 ICFA Beam Dynamics Workshop SLAC March 1-5, 2010
Requests for TR-PES-control of the photon density per pulse-control of the rr (from 10 MHz to kHz regime)-control of the polarization-photon energy between 10 eV and ~10 keV
FLS 2010 ICFA Beam Dynamics Workshop SLAC March 1-5, 2010
Verdi V1818 W
OPA DFG
SincroLock
MIRA seed in scatola Mira 900
Pulse picker
5 W
13 W
MIRA HP
Stretcher/compressor
SincroLock
RegA exit:50 fs pulses5 µJ per pulseR.R. 250 KHzλ=800 nm
OPA:< 60 fs1200-2400 nm160 nJ
DFG:2.5-15 µm10 nJ
1-10 MHz25 nJ per pulse
83,28 MHz50 nJ per pulse
Time-Resolved and Angle Resolved Photoelectron Spectroscopy – TR-ARPES and Time-Resolved and Spin Resolved ARPES – TR-SR-ARPES(started 2006)
ObjectivesScope of the project is to design and built an angle resolved and time resolved photoemission system with a spin detector.
10 K Minimum Temperature on the Sample6 degrees of Freedom motorizedsub meV Resolution40 degrees Angular AcceptanceMax Ang Resolution 0.1 degreesPlug and play upgradable for Spin detection
FLS 2010 ICFA Beam Dynamics Workshop SLAC March 1-5, 2010
Spin states dynamicsObjectiveThe goal of this project is to measure the spin resolved band dispersion and spin dynamics in solid by harmonics and high harmonics generated from a 250 kHz Ti:SA amplified source
Time-of-Flight analyser@ high operating frequency (up to 5 MHz)
Electron detector Mott polarimeter
Collaboration with 4GLS (E. Seddon and C. Cacho)
Two orthogonal Mott-detectors to measure V and H spin components
FLS 2010 ICFA Beam Dynamics Workshop SLAC March 1-5, 2010
Test of the SR-TR ToF on the Au(111) surface states
TR- and AR-Photoemission
Time and Spin resolved experiments
Fermi surface mapping
Osterwalder et al. PRB 69 pp.241401R, 2004)
Spin-orbit coupling )(21
2 pVSc
HSO
×∇⋅=
)3cos(2 2 zSO uSuS
cpH
⋅+⋅= ϕβα ϕ
ϕϕ 6cos),(3sin),(),()( 630 zrVzrVzrVrV ++=
ϕβα uzV +=∇ rupp
=
z
ruϕu
ϕ
FLS 2010 ICFA Beam Dynamics Workshop SLAC March 1-5, 2010
Comparison between the 1kHz and 250kHz laser system
1kHz laser systemTotal time = 4hTotal statistic = 4*23400 e-
250 kHz laser systemTotal time = 1’ 20’’Total statistic = 4*22400 e-
Space Charge Effects
FLS 2010 ICFA Beam Dynamics Workshop SLAC March 1-5, 2010
Angular distribution
Total time = 2h (2 min/scan)Teta = +/- 22 degLow angle resolution
E0 = 0.26 eVm* = 0.134k0 = 0.011 Å-1
Vacuum level = 5.49 eV
FLS 2010 ICFA Beam Dynamics Workshop SLAC March 1-5, 2010
High resolution of the SS energy position
E0 = 260 meVm* = 0.134k0 = 0.011 Å-1
EF
Spin integrated Intensity Energy position of the surface states.
( )20||*
2
0 2kk
mEE ±⋅+=±
Determination of the SS kinetic energy positionwith very high precision (±2meV).
FLS 2010 ICFA Beam Dynamics Workshop SLAC March 1-5, 2010
Future Light Sources 1
ANL-08/39BNL-81895-2008LBNL-1090E-2009SLAC-R-917Science and Technologyof Future Light Sources
HR-PES
TR-PES
FLS 2010 ICFA Beam Dynamics Workshop SLAC March 1-5, 2010
Future Light Sources 2
ANL-08/39BNL-81895-2008LBNL-1090E-2009SLAC-R-917Science and Technology of FutureLight Sources
Monochrom.
High spatial resolution PES
FLS 2010 ICFA Beam Dynamics Workshop SLAC March 1-5, 2010
Conclusions• TR and SR PE-spectroscopy:1. Control of the photon density in the probing pulse2. Selective pumping excitation3. Controlled repetition rate (from kHz uo to MHz)4. Photon energy range from few eV up to few keV5. Very low temperature sample holder ( 6-degrees freedom)
• Potential results:1. Dynamics of the Fermi surfaces2. Electron-boson and electron-electron interactions in
condensed matter (CDW, SDW and SC transition)3. Electronic and magnetic structure of LDM4. Dynamics of the VB and core elctrons