Exciting core-level spectroscopy

TL;DR

This paper presents an ab initio method using many-body perturbation theory and the Bethe-Salpeter equation to accurately compute x-ray absorption spectra across various materials, highlighting its advantages over traditional supercell approaches.

Contribution

It introduces a comprehensive all-electron framework for core-level spectroscopy based on many-body perturbation theory, addressing limitations of existing supercell methods.

Findings

Accurately models exciton binding energies and spectra across different materials.

Identifies conditions where supercell core-hole approach fails.

Provides insights into exciton characteristics in core-level excitations.

Abstract

We delineate an ab initio approach for obtaining x-ray absorption spectra as provided by many-body perturbation theory, together with its realization within an all-electron framework. Employing the Bethe-Salpeter equation, we address excitations from different absorption edges in a broad range of material classes, analyzing exciton binding strengths and character. We also discuss when the supercell core-hole approach is likely to fail.