Resonant inelastic x-ray scattering beyond the quasiparticle approximation
ORAL
Abstract
Resonant inelastic x-ray scattering (RIXS) provides unprecedented experimental access to the fundamental excitations and dynamical responses of correlated materials. Recently, first-principle methods, e.g. based on solving the Bethe-Salpeter equation (BSE), have succeeded in calculating the quasiparticle contribution to RIXS that reflects the underlying band-structure. However, this neglects the important contribution of secondary excitations that are the signatures of the correlated response of the probed material. We significantly improve the BSE description of RIXS by invoking a quasiboson model to describe these secondary excitations in a manner akin to the classic theory of Mahan, Nozières & Dominicis [1,2]. We generate the quasiboson excitation spectrum (e.g. plasmons and secondary electron-hole pairs) through a real-time time-dependent density functional theory calculation of the charge density response to the initial core-level excitation. Our new methodology succeeds at accurately reproducing the experimental RIXS spectrum at the Fe L3 edge of the benchmark correlated metal BaFe2As2, including both quasiparticle and correlated contributions [3].
[1] Mahan, Phys Rev 163, 612 (1967).
[2] Nozières & de Dominicis, Phys Rev 178, 1097 (1969).
[3] Gilmore et al., Phys Rev X 11, 031013 (2021).
[1] Mahan, Phys Rev 163, 612 (1967).
[2] Nozières & de Dominicis, Phys Rev 178, 1097 (1969).
[3] Gilmore et al., Phys Rev X 11, 031013 (2021).
*This work was supported by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, USA as part of the Computational Materials Science Program through the Center for Computational Design of Functional Strongly Correlated Materials and Theoretical Spectroscopy.
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Publication: Gilmore et al., Phys Rev X 11, 031013 (2021)
Presenters
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Keith Gilmore
- Humboldt University of Berlin