Band structure of tungsten oxide W$_{20}$O$_{58}$ with ideal octahedra

TL;DR

This study investigates the electronic band structure and density of states of W20O58 with ideal octahedral arrangements using density functional theory, highlighting the role of specific tungsten atoms near vacancies.

Contribution

First detailed DFT analysis of W20O58's electronic structure emphasizing the contribution of tungsten atoms around vacancies.

Findings

5d orbitals of tungsten dominate near the Fermi level

Vacancy ordering influences electronic properties

Specific tungsten atoms are key to low-energy behavior

Abstract

The band structure, density of states, and the Fermi surface of a tungsten oxide WO$_{2.9}$ with idealized crystal structure (ideal octahedra WO$_6$ creating a "square lattice") is obtained within the density functional theory in the generalized gradient approximation. Because of the oxygen vacancies ordering this system is equivalent to the compound W$_{20}$O$_{58}$ (Magn\'{e}li phase), which has 78 atoms in unit cell. We show that 5$d$-orbitals of tungsten atoms located immediately around the voids in the zigzag chains of edge-sharing octahedra give the dominant contribution near the Fermi level. These particular tungsten atoms are responsible of a low-energy properties of the system.