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Time and Spin Resolved PES Fulvio Parmigiani Department of Physics, University of Trieste

Time and Spin Resolved PES Fulvio Parmigiani Department of Physics, University of Trieste and FERMI@elettra.

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Time and Spin Resolved PES Fulvio Parmigiani Department of Physics, University of Trieste

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  1. Time and Spin Resolved PES Fulvio Parmigiani Department of Physics, University of Trieste and FERMI@elettra

  2. 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 for photoemission experiments in the time-domain, whereas longer laser pulses (1-5 ps) provided by FT limited coherent sources can be used for photoemission experiments in the frequency (energy) domain with unrecorded resolving power. Experimental techniques must be brought to bear in which band-structure specificity are combined with time resolution. Angle resolved photoemission is particularly suited for such experiments.

  3. Up to 10 keV X-ray standing wave Space & Time Resol. Core-levels I(,) Photo-e- diff./holog. Kinetic Energy + Other spectroscopies: XES, XAS,… Next gen. detector & Low-T sample goniometer Emission angle A few new directions in photoemission measurements Curtesy C. Fadley, UC Davis & ALS Probe Pulse  inc Ultrahigh Vacuum  Pump Pulse y NiO(001) x z Energy Angle W(110) Valence-levels

  4. The 10-18 s Challenge with 0.1-1 keV soft X-ray Nature Physics, June 2007

  5. LDM Carlo Callegari: LDM coordinator F. Stienkemeir: End station spoke person COHERENCE+TUNABILITY+POLARIZATION Cluster and nanoparticle spectroscopy Spokespersons: 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)

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

  7. sp-band BCS SC- MgB2 doped-C60 Intercalated Graphite LaBaCuO4 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). HTSCs ? e-ph

  8. fcc-fcc isostructural transition: • 15% volume collapse • cell-length : 5.1612 4.677 • cell-volume : 137.4 102.3 • symmetry: F m -3 m • Curie Weiss magnetism-Pauli Magnetism (zero moment) Dynamics of the volume collapse • alpha-gamma phase transition in cerium: • Promotional Model ? • Mott transition ? • Kondo Volume Collapse ? Light induced shock-wave

  9. Photoelectron Spectroscopy CO adsorption C1s, O1s and Pt4f XPS 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.

  10. More realistic look at low-energy inelastic mean free paths--theory S.F. Mao and Z.J. Ding, Hefei (TBP)

  11. VOLPE project: VOLume PhotoEmission with Synchotron Radiation Team: INFM-Lab. TASC ELETTRA Univ. Rome III, EPFL LURE ESRF (ID16) 71 meV @ 5933 eV 50 meV analyser Panaccione et al. NIMA (2005) Torelli et al., Rev.Sci. Instr. 76, 023909 (2005) High Resolution /High Flux beamline: ID16 @ ESRF

  12. 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

  13. SincroLock OPA DFG Stretcher/compressor MIRA seed in scatola Mira 900 OPA: < 60 fs 1200-2400 nm 160 nJ 5 W DFG: 2.5-15 m 10 nJ RegA exit: 50 fs pulses 5 J per pulse R.R. 250 KHz =800 nm Verdi V18 18 W 13 W SincroLock MIRA HP 1-10 MHz25 nJ per pulse Pulse picker 83,28 MHz 50 nJ per pulse • Time-Resolved and Angle Resolved Photoelectron Spectroscopy – TR-ARPES and Time-Resolved and Spin Resolved ARPES – TR-SR-ARPES (started 2006) • Objectives • Scope 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 Sample 6 degrees of Freedom motorized sub meV Resolution 40 degrees Angular Acceptance Max Ang Resolution 0.1 degrees Plug and play upgradable for Spin detection

  14. Spin states dynamics Objective The 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) Two orthogonal Mott-detectors to measure V and H spin components Collaboration with 4GLS (E. Seddon and C. Cacho) Electron detector Mott polarimeter

  15. Test of the SR-TR ToF on the Au(111) surface states Spin-orbit coupling • TR- and AR-Photoemission • Time and Spin resolved experiments • Fermi surface mapping Osterwalder et al. PRB 69 pp.241401R, 2004)

  16. Comparison between the 1kHz and 250kHz laser system 1kHz laser system Total time = 4h Total statistic = 4*23400 e- 250 kHz laser system Total time = 1’ 20’’ Total statistic = 4*22400 e- Space Charge Effects

  17. Angular distribution Total time = 2h (2 min/scan) Teta = +/- 22 deg Low angle resolution E0 = 0.26 eV m* = 0.134 k0 = 0.011 Å-1 Vacuum level = 5.49 eV

  18. EF High resolution of the SS energy position Spin integrated Intensity Energy position of the surface states. Determination of the SS kinetic energy position with very high precision (±2meV). E0 = 260 meV m* = 0.134 k0 = 0.011 Å-1

  19. Future Light Sources 1 TR-PES HR-PES ANL-08/39 BNL-81895-2008 LBNL-1090E-2009 SLAC-R-917 Science and Technology of Future Light Sources

  20. Future Light Sources 2 High spatial resolution PES ANL-08/39 BNL-81895-2008 LBNL-1090E-2009 SLAC-R-917 Science and Technology of Future Light Sources Monochrom.

  21. Conclusions • TR and SR PE-spectroscopy: • Control of the photon density in the probing pulse • Selective pumping excitation • Controlled repetition rate (from kHz uo to MHz) • Photon energy range from few eV up to few keV • Very low temperature sample holder ( 6-degrees freedom) • Potential results: • Dynamics of the Fermi surfaces • Electron-boson and electron-electron interactions in condensed matter (CDW, SDW and SC transition) • Electronic and magnetic structure of LDM • Dynamics of the VB and core elctrons

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