The electronic structure and the phases of BaVS3

TL;DR

This paper investigates the electronic structure and phase behavior of BaVS3, proposing a minimal model based on ARPES data to understand its metal-insulator transition and magnetic properties under various conditions.

Contribution

It introduces a lattice fermion model for BaVS3 that captures its complex phases and magnetic order, aiding understanding of its metal-insulator transition and related phenomena.

Findings

Coexistence of wide-band and narrow-band electrons governs BaVS3 behavior

Field-induced insulator-to-metal transition observed at subcritical pressures

Evidence of magnetic order in high-pressure metallic phase

Abstract

BaVS3 is a moderately correlated d-electron system with a rich phase diagram. To construct the corresponding minimal electronic model, one has to decide which d-states are occupied, and to which extent. The ARPES experiment presented here shows that the behavior of BaVS3 is governed by the coexistence of wide-band (A_1g) and narrow-band (twofold degenerate E) d-electrons. We sketch a lattice fermion model which may serve as a minimal model of BaVS3. This serves foremost for the understanding of the metal-insulator in pure BaVS3 and its absence in some related compounds. The nature of the low temperature magnetic order differs for several systems which may be described in terms of the same electron model. We describe several recent experiments which give information about magnetic order at high pressures. In particular, we discuss field-induced insulator-to-metal transition at slightly subcritical pressures, and an evidence for magnetic order in the high-pressure metallic phase. The phase diagram of Sr-doped BaVS3 is also discussed. The complexity of the phases of BaVS3 arises from the fact that it is simultaneously unstable against several kinds of instabilities.