SKM 2023 – scientific programme

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O: Fachverband Oberflächenphysik

O 9: Focus Session: Frontiers of Electronic-Structure Theory I (joint session O/HL)

O 9.2: Talk

Monday, March 27, 2023, 10:45–11:00, TRE Ma

High-throughput absorption spectra obtained by beyond-DFT workflows — •Fabian Peschel, Alexander Buccheri, and Claudia Draxl — Institut für Physik and IRIS Adlershof, Humboldt-Universität zu Berlin, Berlin, Germany

Fully converging ab initio calculations can be a challenging task, in particular when it comes to excited states, which require multiple ground-state calculations for different physical quantities. In this work, we aim at computing highly precise absorption spectra by employing the Bethe-Salpeter equation of many-body perturbation theory, as implemented in the all-electron full-potential package exciting [1,2]. To obtain benchmark data for a wide range of material classes, we have developed workflows where Python tools automatically create input files, start calculations, and evaluate results. For each material, all relevant input parameters, such as the number of k-points for the Brillouin-zone sampling, basis-set basis cutoff and the number of unoccupied states, are varied until the targeted convergence criteria are reached. With the help of a workflow manager, the calculations can be executed in a high-throughput fashion on a high-performance computing cluster. We demonstrate our approach with core-level spectra of elemental and binary solids, and provide an in-depth analysis of the obtained data. This work is carried out in the framework of the NOMAD Center of Excellence [3] and the CRC FONDA [4].

[1] A. Gulans et al., J. Phys. Condens. Matter 26, 363202 (2014). [2] C. Vorwerk, B. Aurich, C. Cocchi, and C. Draxl, Electron. Struct. 1, 037001 (2019). [3] https://nomad-coe.eu [4] https://fonda.hu-berlin.de