Time and Spin Resolved PES - Stanford University · 2012. 3. 5. · FLS 2010 ICFA Beam Dynamics...

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


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.


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


The 10-18 s Challenge with 0.1-1 keV soft X-ray

Nature Physics, June 2007


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


Y. L. Chen, W.S. Lee and ZX. Shen- PNAS 106, 963 (2009)


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


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


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.

http://en.wikipedia.org/wiki/ARPES�

http://en.wikipedia.org/wiki/Brillouin_zone�

http://en.wikipedia.org/wiki/Brillouin_zone�

http://en.wikipedia.org/wiki/BSCCO�


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


Si

IMFP

(A)

E-EF-φ (eV)

101 102 1030

10

20

30

40


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


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


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


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


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


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


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


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


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).


Future Light Sources 1

ANL-08/39BNL-81895-2008LBNL-1090E-2009SLAC-R-917Science and Technologyof Future Light Sources

HR-PES

TR-PES


Future Light Sources 2

ANL-08/39BNL-81895-2008LBNL-1090E-2009SLAC-R-917Science and Technology of FutureLight Sources

Monochrom.

High spatial resolution PES


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

Time and Spin Resolved PES - Stanford University · 2012. 3. 5. · FLS 2010 ICFA Beam Dynamics...

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