SKM 2021 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 3: Poster Session I
HL 3.21: Poster
Montag, 27. September 2021, 10:00–13:00, P
Implementation of the Bethe-Salpeter Equation in the Spex Code — •Jörn Stöhler1,2, Dmitrii Nabok1, Christoph Friedrich1, and Stefan Blügel1 — 1Forschungszentrum Jülich and JARA, Germany — 2RWTH Aachen University, Germany
The Bethe-Salpeter Equation (BSE) and GW approximation are two many-body perturbation theory techniques that together form the state-of-the-art method to include electron-hole interaction in periodic systems. The BSE has proven to be the most accurate tool to compute optical absorption for the valence and core energy region, as well as electron energy loss. In recent developments the BSE has been applied to compute the exciton band dispersion and exciton effective masses, inelastic electron scattering, and many more.
We have implemented the BSE in the SPEX code, a full-potential linearized augmented planewave (FLAPW) code that supports a range of Green function based methods including the GW approximation, optical spectra in the random phase approximation, and more. The BSE is run on top of a one-shot G0 W0 calculation with SPEX, or directly on top of the underlying density functional theory (DFT) calculations from FLEUR.
Our code has been tested for various bulk, layered and monolayer semiconductors, among them LiF and MoS2, and includes spin-orbit coupling. The results agree with the literature. We also use the crystal symmetries to achieve a significant computational speedup, and maintain good scalability of the code for parallel computing.