Identification of a monoclinic metallic state in VO2 from a modified first-principles approach

TL;DR

This paper introduces a modified first-principles approach to accurately model VO2's phases, revealing a ferromagnetic monoclinic metallic state and elucidating the decoupled structural and electronic transitions.

Contribution

The study develops a novel computational method that captures the stability and electronic structure of VO2 phases, explaining the monoclinic metallic state and transition mechanisms.

Findings

Identification of a ferromagnetic monoclinic metallic state.

Explanation of the decoupled structural and electronic transitions.

Insight into metal-insulator transition mechanisms in correlated systems.

Abstract

Metal-insulator transition underlies many remarkable and technologically important phenomena in VO2. Even though its monoclinic structure had before been the reserve of the insulating state, recent experiments have observed an unexpected monoclinic metallic state. Here we use a modified approach combining first-principles calculations with orbital-biased potentials to reproduce the correct stability ordering and electronic structure of different phases of VO2. We identify a ferromagnetic monoclinic metal that is likely to be the experimentally observed mysterious metastable state. Furthermore, our calculations show that an isostructural insulator-metal electronic transition is followed by the lattice distortion from the monoclinic structure to the rutile structure. These results not only explain the experimental observations of the monoclinic metallic state and the decoupled structural and electronic transitions of VO2, but also provide a understanding for the metal-insulator transition in other strongly correlated d electron systems.