Effects of strain on the electronic structure of VO_2

TL;DR

This study uses cluster-DMFT calculations to explore how strain affects the electronic structure and gap formation in VO_2 across different phases and geometries, revealing the dominant role of bandwidth changes.

Contribution

It introduces a detailed computational analysis of strain effects on VO_2's electronic properties, emphasizing the importance of bandwidth over Peierls splitting in gap formation.

Findings

Bandwidth increase under compression influences the gap more than Peierls splitting.

Strain along the rutile c-axis significantly alters VO_2's electronic structure.

Different geometries affect the electronic properties of VO_2 in both phases.

Abstract

We present cluster-DMFT (CTQMC) calculations based on a downfolded tight-binding model in order to study the electronic structure of vanadium dioxide (VO_2) both in the low-temperature (M_1) and high-temperature (rutile) phases. Motivated by the recent efforts directed towards tuning the physical properties of VO_2 by depositing films on different supporting surfaces of different orientations we performed calculations for different geometries for both phases. In order to investigate the effects of the different growing geometries we applied both contraction and expansion for the lattice parameter along the rutile c-axis in the 3-dimensional translationally invariant systems miming the real situation. Our main focus is to identify the mechanisms governing the formation of the gap characterizing the M_1 phase and its dependence on strain. We found that the increase of the band-width with compression along the axis corresponding to the rutile c-axis is more important than the Peierls bonding-antibonding splitting.