Correlated metallic state of vanadium dioxide

TL;DR

This paper investigates the metallic state of VO₂, revealing that electronic correlations dominate charge dynamics and challenge the standard quasiparticle conduction model, especially in regimes with extremely short mean free paths.

Contribution

It provides new insights into the charge transport mechanism in VO₂, emphasizing the role of electronic correlations over electron-phonon interactions.

Findings

Electronic correlations govern charge dynamics in metallic VO₂.

Standard quasiparticle picture is invalid in this regime.

Metallic VO₂ violates the Ioffe-Regel-Mott limit.

Abstract

The metal-insulator transition and unconventional metallic transport in vanadium dioxide (VO$_2$) are investigated with a combination of spectroscopic ellipsometry and reflectance measurements. The data indicates that electronic correlations, not electron-phonon interactions, govern charge dynamics in the metallic state of VO$_2$. This study focuses on the frequency and temperature dependence of the conductivity in the regime of extremely short mean free path violating the Ioffe-Regel-Mott limit of metallic transport. The standard quasiparticle picture of charge conduction is found to be untenable in metallic VO$_2$.