Regensburg 2019 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 78: Electronic Structure of Surfaces I: Photoelectron Spectroscopy
O 78.1: Vortrag
Donnerstag, 4. April 2019, 10:30–10:45, H14
Multidimensional photoemission and the "Inverse LEED State" — •Benedikt Schönhense1, Katerina Medjanik2, Sergey Babenkov2, Dmitry Vasilyev2, Sergey Chernov2, Hans-Joachim Elmers2, and Gerd Schönhense2 — 1Imperial College London, Dept. of Bioengineering, UK — 2Johannes Gutenberg-Universität, Institut für Physik, D-55099 Mainz, Germany
Using a high-energy version of the time-of-flight k-space microscope we recorded I(EB, k) data arrays at many photon energies in the range of 2.6 to 7 keV at the new hard X-ray beamline P22 at PETRA III (DESY, Hamburg), extending our earlier work at lower energies [1]. Full-field k-imaging of many Brillouin zones (BZs) paves the way to a new type of photoemission experiment, which was impossible with conventional k-microscopes (imaging typically one BZ). The final state in photoemission is a "time-reversed LEED state" [2], since it contains the contribution of all scattering paths experienced by the outgoing electron wave. At keV energies, the valence-band pattern contains substantial contributions from X-ray photoelectron diffraction XPD, which are superimposed on the band features. The results confirm our new model of XPD on the basis of the Laue-equations [3]. The high count rates pave the way towards spin-resolved HAXPES using an imaging spin filter.
[1] K. Medjanik et al., Nature Mat. 16, 615 (2017); [2] S. Hüfner, Photoelectron Spectroscopy, Springer Berlin, (2003); [3] G. Schönhense et al., arXiv: 1806.05871 (2018).