Role of c-axis pairs in V2O3 from the band-structure point of view

TL;DR

This paper investigates the band structure of V2O3, revealing that multiple hopping integrals, not just vertical V-V pair coupling, significantly influence the $a_{1g}$ band shape, challenging previous interpretations.

Contribution

It demonstrates that other hopping integrals are as important as vertical pair coupling in shaping the $a_{1g}$ band in V2O3, using tight-binding and NMTO downfolding methods.

Findings

Multiple hopping integrals influence the $a_{1g}$ band shape.

Vertical V-V pair coupling is not the sole factor.

Band structure interpretation needs revision.

Abstract

The common interpretation of the LDA band structure of V$_{2}$O$_{3}$ is that the apparent splitting of the $a_{1g}$ band into a low intensity structure deep below the Fermi energy and a high intensity feature above it, is due to the bonding-antibonding coupling of the vertical V-V pair. Using tight-binding fitting to --as well as first-principles NMTO downfolding of-- the spin-up LDA+U $a_{1g}$ band, we show that there are other hopping integrals which are equally important for the band shape as the integral for hopping between the partners of the pair.