Effects of electron-phonon coupling on absorption spectrum: K edge of hexagonal boron nitride

Author(s): Ferenc Karsai, Moritz Humer, Flage-Larsen Espen, Blaha Peter, Georg Kresse
Abstract: A detailed analysis of the theoretical x-ray absorption near-edge structures (XANES) for the boron and nitrogen K edge in hexagonal boron nitride (h-BN) employing density-functional theory calculations is presented. The supercell core-hole method and the Bethe-Salpeter equation are used for the description of electron-hole interactions. The calculations are carried out with two different codes, the vasp and the wien2k codes, employing the projector augmented-wave and the full-potential linear augmented-plane-wave methods, respectively. We find close agreement between spectra obtained from the two codes and between calculations using the supercell core-hole method and the Bethe-Salpeter approach. All our calculations, as well as previous calculations using the ground-state structure, yield a single 2pσ∗ peak in the boron K-edge spectrum and hence fail to describe the experimental double-peak structure. We find that the inclusion of electron-phonon interactions is crucial to obtain the experimentally observed double-peak structure. We include these effects fully parameter free and ab initio using a one-shot sampling method and obtain excellent agreement with experiment.
Organisation(s): Computational Materials Physics
External organisation(s): SINTEF The Foundation for Scientific and Industrial Research at the Norwegian Institute of Technology (NTH), Technische Universität Wien
Journal: Physical Review B
Volume: 98
No. of pages: 10
ISSN: 2469-9950
DOI: https://doi.org/10.1103/PhysRevB.98.235205
Publication date: 12-2018
Peer reviewed: Yes
Austrian Fields of Science 2012: 103018 Materials physics
Keywords
ASJC Scopus subject areas: Electronic, Optical and Magnetic Materials, Condensed Matter Physics
Portal url: https://ucrisportal.univie.ac.at/en/publications/595a5614-e6cb-4290-81b5-366ebe1fce60