Electronic structure of van der Waals ferromagnet CrI$_{3}$ from self consistent vertex corrected GW approaches

TL;DR

This paper investigates the electronic structure of the layered ferromagnet CrI$_{3}$ using advanced self-consistent GW methods, revealing improved band gap predictions and better spectral feature reproduction over traditional approaches.

Contribution

It introduces a self-consistent, vertex-corrected GW approach that surpasses previous methods in accuracy for layered van der Waals ferromagnets.

Findings

Significant improvement in band gap calculation.

Better reproduction of spectral features seen in experiments.

Large non-local effects in polarizability and self energy.

Abstract

Electronic structure of layered van der Waals ferromagnet CrI$_{3}$ is studied with self consistent diagrammatic approaches beyond GW approximation. Considerable improvement in the calculated band gap as compared to the non-self-consistent G0W0 results has been found. Certain spectral features in the valence bands discovered recently by the angle resolved photoemission spectroscopy, are reproduced better when we use full frequency dependent self energy. Density functional theory and quasiparticle self-consistent GW method which are based on frequency-independent self energy are unable to resolve these features. Non-locality effects in the diagrams beyond GW approximation are large for both polarizability and self energy. This finding can potentially have an impact on the development of methods like GW+DMFT.