Cluster model calculations with non-local screening channels of metallic and insulating VO2

TL;DR

This study investigates the electronic structure changes in VO2 during the metal-insulator transition using cluster model calculations that incorporate non-local screening channels, revealing the role of coherent and Hubbard screening in different phases.

Contribution

The paper introduces a cluster model calculation approach with non-local screening channels to explain VO2's electronic structure changes across the transition.

Findings

Coherent screening explains the metallic phase's Fermi level feature.

Hubbard screening leads to band gap opening in the insulating phase.

Electronic structure changes are linked to non-local screening channels.

Abstract

We studied the changes in the electronic structure of VO2 across the metal-insulator transition. The main technique was cluster model calculations with non-local screening channels. The calculation included a screening from a coherent state at the Fermi level in the metallic phase, and a screening from a Hubbard charge fluctuation within the V-V dimmer in the insulating phase. The calculation results are compared to previous photoemission and X-ray absorption spectra. The coherent feature at the Fermi level in the metallic phase is due to the coherent screening. But the Hubbard screened state in the insulating phase appears at higher energies opening the band gap. The changes in the electronic structure of VO2 are thus related to the non-local screening channels.