Electron Correlation driven Metal-Insulator transition in Strained and Disordered VO2 films

TL;DR

This study explores how strain and disorder influence the metal-insulator transition in VO2, revealing that electron correlations primarily drive the transition, which can be finely tuned through these parameters.

Contribution

It demonstrates that the MIT in strained and disordered VO2 is driven by electron correlation effects, providing insights into controlling the transition via strain and disorder.

Findings

MIT in strained VO2 is of the Filling Control type.

MIT in disordered VO2 is driven by electron correlation.

Strain and disorder can be used to tune the transition features.

Abstract

The Metal-Insulator transition (MIT) in VO2 is characterized by the complex interplay among lattice, electronic and orbital degrees of freedom. In this contribution we investigated the strain-modulation of the orbital hierarchy and the influence over macroscopic properties of the metallic phase of VO2 such as Fermi Level (FL) population and metallicity, i.e., the material ability to screen an electric field, by means of temperature-dependent X-ray Absorption Near Edge Structure (XANES) and Resonant Photoemission spectroscopy (ResPES). We demonstrate that the MIT in strained VO2 is of the Filling Control type, hence it is generated by electron correlation effects. In addition, we show that the MIT in Nanostructured (NS) disordered VO2, where the structural phase transition is quenched, is driven by electron correlation. Therefore a fine tuning of the correlation could lead to a precise control and tuning of the transition features.