VO2: a two-fluid incoherent metal?

TL;DR

This study uses ab initio LDA+DMFT calculations to show that metallic VO2 lacks Fermi liquid behavior, supporting the idea that its insulator-metal transition is an orbital-selective Mott transition, aligning well with experimental data.

Contribution

It provides the first ab initio evidence that VO2's metallic phase is a non-Fermi liquid, proposing an orbital-selective Mott transition as the underlying mechanism.

Findings

No correlated Fermi liquid behavior in metallic VO2.

Excellent agreement with photoemission and X-ray absorption data.

Supports orbital-selective Mott transition as the insulator-metal transition mechanism.

Abstract

We present {\it ab initio} LDA+DMFT results for the many-particle density of states of $VO_{2}$ on the metallic side of the strongly first-order ($T$-driven) insulator-metal transition. In strong contrast to LDA predictions, there is {\it no} remnant of even correlated Fermi liquid behavior in the correlated metal. Excellent quantitative agreement with published photoemission and X-ray absorption experiments is found in the metallic phase. We argue that the absence of FL-quasiparticles provides a natural explanation for the bad-metallic transport for $T > 340 K$. Based on this agreement, we propose that the I-M transition in $VO_{2}$ is an orbital-selective Mott transition, and point out the relevance of orbital resolved one-electron and optical spectroscopy to resolve this outstanding issue.