We explore the electronic structure of paramagnetic CrSBr by comparative first principles calculations and angle-resolved photoemission spectroscopy. We theoretically approximate the paramagnetic phase using a supercell hosting spin configurations with broken long-range order and applying quasiparticle self-consistent GW theory, without and with the inclusion of excitonic vertex corrections to the screened Coulomb interaction (QSGW and QSGW^, respectively). Comparing the quasi-particle band structure calculations to angle-resolved photoemission data collected at 200 K results in excellent agreement. This allows us to qualitatively explain the significant broadening of some bands as arising from the broken magnetic long-range order and/or electronic dispersion perpendicular to the quasi two-dimensional layers of the crystal structure. The experimental band gap at 200 K is found to be at least 1.51 eV at 200 K. At lower temperature, no photoemission data can be collected as a result of charging effects, pointing towards a significantly larger gap, which is consistent with the calculated band gap of ≈ 2.1 eV.
@article{arxiv.2303.01292,
title = {Paramagnetic Electronic Structure of CrSBr: Comparison between Ab Initio GW Theory and Angle-Resolved Photoemission Spectroscopy},
author = {Marco Bianchi and Swagata Acharya and Florian Dirnberger and Julian Klein and Dimitar Pashov and Kseniia Mosina and Zdenek Sofer and Alexander N. Rudenko and Mikhail I. Katsnelson and Mark van Schilfgaarde and Malte Rösner and Philip Hofmann},
journal= {arXiv preprint arXiv:2303.01292},
year = {2023}
}