The common interpretation of the local-density approximation (LDA) band structure of ${\mathrm{V}}_2{\mathrm{O}}_3$ 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 Nth order muffin-tin orbital (NMTO) downfolding of—the spin-up $\mathrm{LDA}+U$ $a_{1g}$ 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.

• Received 19 March 2003

DOI:https://doi.org/10.1103/PhysRevB.68.113105