Electronic structure of van der Waals ferromagnet <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mi>CrI</mml:mi><mml:mn>3</mml:mn></mml:msub></mml:math> from self-consistent vertex corrected <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mi>G</mml:mi><mml:mi>W</mml:mi></mml:mrow></mml:math> approaches
Andrey L. Kutepov
Abstract
The electronic structure of layered van der Waals ferromagnet ${\mathrm{CrI}}_{3}$ is studied with self-consistent diagrammatic approaches beyond GW approximation. Considerable improvement in the calculated band gap as compared to the non-self-consistent ${G}_{0}{W}_{0}$ results has been found. Certain spectral features in the valence bands discovered recently by 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. Nonlocality 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$+$dynamical mean field theory.