Berlin 2024 – wissenschaftliches Programm
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DS: Fachverband Dünne Schichten
DS 21: Optical Analysis of Thin Films
DS 21.2: Vortrag
Freitag, 22. März 2024, 10:00–10:15, A 053
Theory of X-ray excitation of two-dimensional materials — Dominik Christiansen1, Ivan Maliyov2, •Joris Sturm1, Malte Selig1, Marco Bernardi2, and Andreas Knorr1 — 1Institut für Theoretische Physik, Nichtlineare Optik und Quantenelektronik, Technische Universität Berlin, Hardenbergstr. 36, 10623 Berlin, Germany — 2Department of Applied Physics and Materials Science, California Institute of Technology, Pasadena, CA 91125, USA
In this contribution, we present a combined theory of X-ray Bloch - and Maxwell’s equations to describe X-ray absorption experiments like XANES and EXAFS. Particularly crucial in the calculation of EXAFS spectra is a detailed knwoledge about the electronic structure and the electron - X-ray interaction matrix elements. In contrast to prior work, where a semi-empirical tight-binding approach was employed [1], we have improved our methodology by including ab initio electronic structure calculations. As a proof of principle we calculated the absorption spectrum of graphene which recovers now spectral signals missing in the previous approach [1].
[1] Christiansen, Dominik, et al., Physical Review Research 5.2 (2023): 023002.
[2] Christiansen, Dominik, et al., "Joint ab initio and Maxwell-Bloch approaches for the description of X-ray excitations of two-dimensional materials" (in preparation)
Keywords: X-ray absorption; XANES; EXAFS