Electronic correlations in vanadium chalcogenides: BaVSe3 versus BaVS3

TL;DR

This study compares the electronic behaviors of BaVS3 and BaVSe3, revealing how subtle differences in electron interactions influence their distinct low-temperature phases, with BaVSe3 remaining metallic unlike BaVS3.

Contribution

The paper combines advanced theoretical methods to identify subtle electronic differences explaining the contrasting low-temperature behaviors of BaVS3 and BaVSe3.

Findings

BaVSe3 remains metallic down to zero temperature.

Smaller Hubbard U and increased Hund's J are key factors.

Differences in electron correlations explain phase behavior.

Abstract

Albeit structurally and electronically very similar, at low temperature the quasi-one-dimensional vanadium sulfide BaVS3 shows a metal-to-insulator transition via the appearance of a charge-density-wave state, while BaVSe3 apparently remains metallic down to zero temperature. This different behavior upon cooling is studied by means of density functional theory and its combination with the dynamical mean-field theory and the rotationally-invariant slave-boson method. We reveal several subtle differences between these chalcogenides that provide indications for the deviant behavior of BaVSe3 at low temperature. In this regard, a smaller Hubbard U in line with an increased relevance of the Hund's exchange J plays a vital role.