Dresden 2017 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 24: Electronic-Structure Theory: New Concepts and Developments in Density Functional Theory and Beyond - II
HL 24.5: Talk
Monday, March 20, 2017, 16:15–16:30, GER 38
Non-linear-screening contributions to photoemission spectra — •Marilena Tzavala1,2, Claudia Rödl1,2,3, and Lucia Reining1,2 — 1Laboratoire des Solides Irradiés, École polytechnique, CNRS, CEA, Université Paris-Saclay, 91128 Palaiseau, France — 2European Theoretical Spectroscopy Facility (ETSF) — 3Institut für Festkörpertheorie und -optik, Friedrich-Schiller-Universität Jena, Max-Wien-Platz 1, 07743 Jena, Germany
The state-of-the-art approach to calculate photoemission spectra of a broad range of materials is many-body perturbation theory in the GW approximation, sometimes combined with a cumulant expansion. The effective interaction that appears in these approaches is screened within the linear-response approximation. However, the photoemission of a core electron or a localized valence electron may be a strong perturbation, which suggests that non-linear screening effects could be important. We propose a formulation of the functional relations between the one-body Green’s function and the screened interaction which is an alternative to Hedin’s equations and which explicitly displays non-linear screening. Using a simple model, we show that exchange-correlation contributions are crucial in order to capture the non-linear effects. We also discuss how to apply the scheme to real materials using time-dependent density-functional theory (TDDFT).