Regensburg 2019 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 78: Electronic Structure of Surfaces I: Photoelectron Spectroscopy

O 78.2: Vortrag

Donnerstag, 4. April 2019, 10:45–11:00, H14

Momentum-resolved hard X-ray photoelectron spectroscopy with eliminated diffraction — •S. Babenkov¹, K. Medjanik¹, D. Vasilyev¹, S. Chernov¹, O. Fedchenko¹, C. Schlüter², A. Gloskovskii², Yu. Matveyev², W. Drube², B. Schönhense³, K. Rossnagel^2,4, H.J. Elmers¹, and G. Schönhense¹ — ¹JGU, Inst. für Physik, Mainz — ²DESY, Hamburg — ³Imp. Col. London, Dept. of Bioengineering — ⁴CAU, Inst. für Exp. und Angew. Physik, Kiel

Hard X-ray angular-resolved photoelectron spectroscopy is a powerful tool to study the electronic band dispersions of buried layers and inner interfaces[1]. Up to now, one had to struggle against experimental obstacles such as low cross-section and strong X-ray photoelectron diffraction (XPD) modulating the spectral density of states. Using a combination of a high-energy version of a time-of-flight k-microscope and the high-brilliance hard X-ray beamline P22 at PETRA III, we are able to acquire full I(E_B,k) data arrays up to hν = 7 keV in short time[2] and thus overcome the previous acquisition time limitations. In order to eliminate the XPD modulation[3] we present a novel method: the normalization of the valence band data by high-resolution core-level XPD patterns, measured at the same kinetic energy and k-field of view, reveal the non-modulated spectral removal function. We present valence band dispersions of molybdenum, graphite and the prototypical dichalcogenide TiTe₂ single crystals. [1] A. Gray et al., Nat. Mat. 10, 759 (2011) and Nat. Mat 11, 957 (2012); [2] K. Medjanik et al., Nat. Mat. 16, 615 (2017); [3] G. Schönhense et al., arXiv 1806.05871 (2018).