Time-resolved x-ray photoelectron spectroscopy at FLASH

The technique of time-resolved pump-probe x-ray photoelectron spectroscopy using the free-electron laser in Hamburg (FLASH) is described in detail. Particular foci lie on the macrobunch resolving detection scheme, the role of vacuum space-charge effects and the synchronization of pump and probe lasers. In an exemplary case study, the complete Ta 4f core-level dynamics in the layered charge-density-wave (CDW) compound 1T-TaS2 in response to impulsive optical excitation is measured on the sub-picosecond to nanosecond timescale. The observed multi-component dynamics is related to the intrinsic melting and reformation of the CDW as well as to extrinsic pump-laser-induced vacuum space-charge effects.

[1]  A. Ghorayeb,et al.  Thermal and transport evidence for a phase transition in 1T-TaS2 observed at 282K upon warming , 1984 .

[2]  Stephan Hüfner,et al.  Photoelectron Spectroscopy: Principles and Applications , 2010 .

[3]  S. Johnson,et al.  Nonthermal melting of a charge density wave in TiSe2. , 2011, Physical review letters.

[4]  Jerome B. Hastings,et al.  Gas detectors for x-ray lasers , 2008 .

[5]  L. A. Shmaenok,et al.  Measurement of gigawatt radiation pulses from a vacuum and extreme ultraviolet free-electron laser , 2003 .

[6]  Z. Shen,et al.  Transient Electronic Structure and Melting of a Charge Density Wave in TbTe3 , 2008, Science.

[7]  S. Smaalen,et al.  X-ray crystal-structure refinement of the nearly commensurate phase of 1T-TaS2 in (3+2)-dimensional superspace , 1997 .

[8]  R. Schwall,et al.  Low-temperature specific heat of layered compounds , 1976 .

[9]  S. Doniach,et al.  X-ray photoemission spectroscopy , 1974, Nature.

[10]  N. V. Smith,et al.  Band structures of the layer compounds 1T-TaS2 and 2H-TaSe2 in the presence of commensurate charge-density waves , 1985 .

[11]  H. Dürr,et al.  A new energy and angle resolving electron spectrometer First results , 2011 .

[12]  E. Saldin,et al.  Generation of coherent radiation by a relativistic-electron beam in an undulator , 1979 .

[13]  F Hennies,et al.  Ultrafast melting of a charge-density wave in the Mott insulator 1T-TaS2. , 2010, Physical review letters.

[14]  H. Wiedemann.  Particle accelerator physics , 1993 .

[15]  S. Chambers.  Epitaxial film crystallography by high-energy Auger and X-ray photoelectron diffraction , 1991 .

[16]  Gianluca Geloni,et al.  Few-femtosecond timing at fourth-generation X-ray light sources , 2011 .

[17]  Ivanov,et al.  Theory of high-harmonic generation by low-frequency laser fields. , 1994, Physical review. A, Atomic, molecular, and optical physics.

[18]  Y. Ishida,et al.  Femtosecond core-level photoemision spectroscopy on 1T-TaS 2 using a 60-eV laser source , 2010, 1012.2549.

[19]  John A. Wilson,et al.  Discommensuration Arrays and Broken Hexagonal Symmetry in the Microstructure of the CDW States in 2H-TaSe2 as Revealed by Electron Microscopy , 1982 .

[20]  Hughes,et al.  Site specific photohole screening in a charge density wave. , 1995, Physical review letters.

[21]  A. Cavalleri,et al.  Clocking the melting transition of charge and lattice order in 1T-TaS2 with ultrafast extreme-ultraviolet angle-resolved photoemission spectroscopy. , 2011, Physical review letters.

[22]  G. Margaritondo,et al.  Status and prospects of x-ray free-electron lasers (X-FELs): a simple presentation , 2012 .

[23]  Ryszard S. Romaniuk,et al.  Operation of a free-electron laser from the extreme ultraviolet to the water window , 2007 .

[24]  D. Mihailovic,et al.  Coherent dynamics of macroscopic electronic order through a symmetry breaking transition , 2010, 1006.1815.

[25]  W. Stickle,et al.  Handbook of X-Ray Photoelectron Spectroscopy , 1992 .

[26]  W. Y. Liang,et al.  The reflectivity spectra of some group VA transition metal dichalcogenides , 1975 .

[27]  Wilfried Wurth,et al.  The liquid-liquid phase transition in silicon revealed by snapshots of valence electrons , 2010, Proceedings of the National Academy of Sciences.

[28]  Henry C. Kapteyn,et al.  Direct Observation of Surface Chemistry Using Ultrafast Soft-X-Ray Pulses , 2001 .

[29]  F. Jellinek,et al.  The low-temperature superstructures of 1T-TaSe2 and 2H-TaSe2 , 1980 .

[30]  R. Haight,et al.  Tunable photoemission with harmonics of subpicosecond lasers , 1994 .

[31]  C. Jozwiak,et al.  Vacuum space charge effect in laser-based solid-state photoemission spectroscopy , 2010, 1001.1989.

[32]  Jason R. Dwyer,et al.  Ultrafast electron optics: Propagation dynamics of femtosecond electron packets , 2002 .

[33]  T. Togashi,et al.  Photoemission spectroscopic evidence of gap anisotropy in an f-electron superconductor. , 2005, Physical review letters.

[34]  H. Petek,et al.  Femtosecond time-resolved two-photon photoemission studies of electron dynamics in metals , 1997 .

[35]  E. Tosatti,et al.  Electrical, structural and magnetic properties of pure and doped 1T-TaS2 , 1979 .

[36]  D. R. Penn,et al.  Calculations of electorn inelastic mean free paths. II. Data for 27 elements over the 50–2000 eV range , 1991 .

[37]  A. M. Kondratenko,et al.  GENERATING OF COHERENT RADIATION BY A RELATIVISTIC ELECTRON BEAM IN AN ONDULATOR , 1980 .

[38]  Antoine Georges,et al.  Time evolution of the electronic structure of 1T-TaS2 through the insulator-metal transition. , 2006, Physical review letters.

[39]  K. Rossnagel.  On the origin of charge-density waves in select layered transition-metal dichalcogenides , 2011, Journal of physics. Condensed matter : an Institute of Physics journal.

[40]  L. Kipp,et al.  Vacuum space-charge effects in solid-state photoemission , 2009 .

[41]  N. V. Smith,et al.  XPS density of states of copper, silver, and nickel , 1972 .

[42]  C. Nordling,et al.  Electron Spectroscopy and Chemical Binding , 1966, Nature.

[43]  Ayache,et al.  Thermal conductivity of 1T-TaS2 and 2H-TaSe2. , 1985, Physical review letters.

[44]  J. Feldhaus,et al.  Development of MCP-based photon diagnostics at the TESLA Test Facility at DESY , 2004 .

[45]  A. Einstein.  Über einen die Erzeugung und Verwandlung des Lichtes betreffenden heuristischen Gesichtspunkt [AdP 17, 132 (1905)] , 2005 .

[46]  H. Kapteyn,et al.  The laser-assisted photoelectric effect on surfaces , 2006, 2006 Conference on Lasers and Electro-Optics and 2006 Quantum Electronics and Laser Science Conference.

[47]  F. Rotermund,et al.  Generation of the fourth harmonic of a femtosecond Ti:sapphire laser. , 1998, Optics letters.

[48]  K. Holldack,et al.  Femtosecond undulator radiation from sliced electron bunches. , 2006, Physical review letters.

[49]  M M Murnane,et al.  Bright, coherent, ultrafast soft X-ray harmonics spanning the water window from a tabletop light source. , 2010, Physical review letters.

[50]  F. Parmigiani,et al.  Non-linear photoemission from polycrystalline molybdenum irradiated by 790 nm-150 fs laser pulses , 2001 .

[51]  M. Aeschlimann,et al.  Space charge effects in photoemission with a low repetition, high intensity femtosecond laser source , 2006 .

[52]  Martin Beye,et al.  A femtosecond X-ray/optical cross-correlator , 2008 .

[53]  H. Wabnitz,et al.  The soft x-ray free-electron laser FLASH at DESY: beamlines, diagnostics and end-stations , 2009 .

[54]  K. L. Man,et al.  Low energy electron microscopy and photoemission electron microscopy investigation of graphene , 2012, Journal of physics. Condensed matter : an Institute of Physics journal.

[55]  J. Rayappan,et al.  Thermal properties of 1T-TaS2 at the onset of charge density wave states , 2010 .

[56]  O. Johansen.  Thermal Conductivity of Soils , 1977 .

[57]  R. Pollak,et al.  Charge density waves in layered metals observed by X-ray photoemission , 1976 .

[58]  D. Hilton,et al.  On Photo-Induced Phenomena in Complex Materials : Probing Quasiparticle Dynamics using Infrared and Far-Infrared Pulses( Photo-Induced Phase Transitions and their Dynamics) , 2006 .

[59]  E. C. Robertson.  THERMAL PROPERTIES OF ROCKS , 1988 .

[60]  N. V. Smith,et al.  Spin-orbit coupling in the band structure of reconstructed1T-TaS2 , 2006 .

[61]  Franz Tavella,et al.  The FLASH pump–probe laser system: Setup, characterization and optical beamlines , 2011 .

[62]  C. Steier,et al.  Successful completion of the femtosecond slicing upgrade at the ALS , 2007, 2007 IEEE Particle Accelerator Conference (PAC).

[63]  Wilfried Wurth,et al.  Towards time resolved core level photoelectron spectroscopy with femtosecond x-ray free-electron lasers , 2008 .

[64]  Klaus Sokolowski-Tinten,et al.  Experiments at FLASH , 2009 .

[65]  P. Nicolosi,et al.  First operation of a free-electron laser generating GW power radiation at 32 nm wavelength , 2006 .

[66]  Weida,et al.  Real-time observation of adsorbate atom motion above a metal surface , 2000, Science.

[67]  U. Heinzmann,et al.  Femtosecond time-resolved core-level photoelectron spectroscopy tracking surface photovoltage transients on p–GaAs , 2002 .

[68]  Siarhei Dziarzhytski,et al.  The monochromator beamline at FLASH: performance, capabilities and upgrade plans , 2011, 1301.4087.

[69]  Wilfried Wurth,et al.  Monochromator beamline for FLASH , 2006 .

[70]  A. Georges,et al.  Femtosecond dynamics of electronic states in the Mott insulator 1T-TaS2 by time resolved photoelectron spectroscopy , 2008 .

[71]  S Ueda,et al.  Probing bulk electronic structure with hard X-ray angle-resolved photoemission. , 2011, Nature materials.

[72]  S. Kevan.  Angle-resolved photoemission : theory and current applications , 1992 .

[73]  John M. J. Madey,et al.  First Operation of a Free-Electron Laser , 1977 .

[74]  H. Chapman,et al.  Turning solid aluminium transparent by intense soft X-ray photoionization , 2009 .

[75]  J. Demšar,et al.  Dynamics of photoinduced charge-density-wave to metal phase transition in K0.3MoO3. , 2009, Physical review letters.

[76]  J. C. Kieffer,et al.  Evidence for a structurally-driven insulator-to-metal transition in VO 2 : A view from the ultrafast timescale , 2004, cond-mat/0403214.

[77]  Probing the Electronic Structure of Complex Systems by ARPES , 2003, cond-mat/0307085.

[78]  Takashi Takahashi,et al.  Fe-based superconductors: an angle-resolved photoemission spectroscopy perspective , 2011, 1110.6751.

[79]  Wilfried Wurth,et al.  Performance of the monochromator beamline at FLASH , 2007 .

[80]  A. Sekiyama,et al.  Probing bulk states of correlated electron systems by high-resolution resonance photoemission , 2000, Nature.

[81]  Michael Bauer,et al.  Collapse of long-range charge order tracked by time-resolved photoemission at high momenta , 2011, Nature.

[82]  K. Rossnagel.  Suppression and emergence of charge-density waves at the surfaces of layered 1T-TiSe2 and 1T-TaS2 by in situ Rb deposition , 2010 .

[83]  Z. Hussain,et al.  Temperature-dependent angle-resolved x-ray photoemission study of the valence bands of single-crystal tungsten: Evidence for direct transitions and phonon effects , 1980 .

[84]  Wei Li,et al.  Time-resolved pump-probe experiments beyond the jitter limitations at FLASH , 2009 .

[85]  L. Forró,et al.  Spectral Consequences of Broken Phase Coherence in 1T-TaS2 , 1998 .

[86]  A. Einstein.  Über einen die Erzeugung und Verwandlung des Lichtes betreffenden heuristischen Gesichtspunkt [AdP 17, 132 (1905)] , 2005, Annalen der Physik.

[87]  Glover,et al.  Generation of femtosecond pulses of synchrotron radiation , 2000, Science.

[88]  R. Miller,et al.  Snapshots of cooperative atomic motions in the optical suppression of charge density waves , 2010, Nature.

[89]  Xiaoping Zhou,et al.  Space charge effect and mirror charge effect in photoemission spectroscopy , 2004, cond-mat/0410006.

[90]  S. Eisebitt,et al.  Single-pulse resonant magnetic scattering using a soft x-ray free-electron laser , 2010 .

[91]  F. D. Salvo,et al.  Electronic Conduction Process in 1T-TaS 2 , 1980 .

[92]  E. Rotenberg,et al.  Continuous tuning of electronic correlations by alkali adsorption on layered 1T-TaS2. , 2005, Physical Review Letters.