Unified Band Theoretic Description of Electronic and Magnetic Properties of Vanadium Dioxide Phases

TL;DR

This study demonstrates that band theory, with optimized hybrid functionals, can accurately describe the electronic and magnetic properties of VO2 phases, challenging the necessity of strong correlation models.

Contribution

The paper shows that using advanced band theory methods suffices to explain VO2 phases' properties, reducing reliance on strong correlation theories.

Findings

Accurate modeling of energy gaps and magnetic orderings in VO2 phases.

Identification of a candidate for the metallic monoclinic phase.

Detailed magnetic structure of the M2 monoclinic phase.

Abstract

The debate about whether the insulating phases of vanadium dioxide (VO2) can be described by band theory or must be described by a theory of strong electron correlations remains unresolved even after decades of research. Energy-band calculations using hybrid exchange functionals or including self-energy corrections account for the insulating or metallic nature of different phases, but have not yet successfully accounted for the observed magnetic orderings. Strongly-correlated theories have had limited quantitative success. Here we report that, by using hard pseudopotentials and an optimized hybrid exchange functional, the energy gaps and magnetic orderings of both monoclinic VO2 phases and the metallic nature of the high-temperature rutile phase are consistent with available experimental data, obviating an explicit role for strong correlations. We also report a potential candidate for the newly-found metallic monoclinic phase and present a detailed magnetic structure of the M2 monoclinic phase.