Regensburg 2025 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 37: Correlated Electrons: Poster
TT 37.40: Poster
Mittwoch, 19. März 2025, 15:00–18:00, P4
Excitations and Their Decay: Calculating the Non-Lorentzian Line Shape of Excited States at the Ti L2,3 edge in SrTiO3 — •Sarah L. Görlitz1, Sina Shokri1, Widad Louafi2, Martin Braß1,3, Marc Merstorf1, Jonas Hoecht1, Michelangelo Tagliavini1, Kevin Ackermann1, and Maurits W. Haverkort1 — 1Institut for Theoretical Physics, Heidelberg University, 69120 Heidelberg — 2Laboratory of Theoretical Physics, Faculty of Exact Sciences, University of Bejaia, 06000 Bejaia, Algeria — 3Institute of Solid State Physics, TU Wien, 1040 Vienna, Austria
Understanding electron dynamics in real materials following photon excitations is a challenging task. Ultrafast pump-probe and multi-color experiments require precise control, while strong electron correlations in excited states complicate the theoretical description. Accurate calculations must reproduce absorption line shapes for single-photon absorption, often non-Lorentzian due to multi-channel decay processes.
In this work, we calculate the line shape of Ti 2p → 3d core excitations in SrTiO3. While crystal-field models predict seven delta-function peaks, the real spectrum reveals distinct line widths and non-Lorentzian line shapes. Incorporating Auger-Meitner decay, fluorescence decay, and coupling to the valence-conduction bath continuum, we establish a framework to explain these broadenings. This approach is critical for predicting higher-order response functions, essential for modeling resonant inelastic X-ray scattering (RIXS) and ultrafast spectroscopies, providing insights into the interplay of decay processes and electron dynamics.
Keywords: Ultra-fast dynamics; Electronic decay; Line-width; Core excited states; Anderson Impurity