Importance of interorbital charge transfers for the metal-to-insulator transition of BaVS$_3$

TL;DR

This paper investigates the metal-to-insulator transition in BaVS$_3$ using advanced theoretical methods, revealing that interorbital charge transfers driven by correlation effects are key to understanding the transition.

Contribution

It demonstrates that correlation-induced charge redistribution between orbitals explains experimental observations, resolving previous discrepancies in BaVS$_3$'s MIT.

Findings

Correlation effects cause charge redistribution in BaVS$_3$

Lower occupancy of the g band favors the transition

Explains experimental charge-density wave and local moments

Abstract

The underlying mechanism of the metal-to-insulator transition (MIT) in BaVS$_3$ is investigated, using dynamical mean-field theory in combination with density functional theory. It is shown that correlation effects are responsible for a strong charge redistribution, which lowers the occupancy of the broader \a1g band in favor of the narrower $E_g$ bands. This resolves several discrepancies between band theory and the experimental findings, such as the observed value of the charge-density wave ordering vector associated with the MIT, and the presence of local moments in the metallic phase.