Electronic structure and magnetism in X_xW_{1-x}O_3 (X=Nb,V,Re) from supercell calculations

TL;DR

This study uses supercell calculations to explore how doping affects the electronic structure and potential magnetism in X_xW_{1-x}O_3 compounds, revealing conditions for magnetic moments related to density-of-states features.

Contribution

It provides a detailed analysis of the electronic and magnetic properties of doped XW_{1-x}O_3 using supercell calculations and the virtual crystal approximation, highlighting conditions for magnetism.

Findings

Undoped material is an insulator.

Slight doping turns it into a metal.

Magnetic moments appear when Fermi energy aligns with steep DOS features.

Abstract

Some doped semiconductors have recently been shown to display superconductivity or weak ferromagnetism. Here we investigate the electronic structure and conditions for magnetism in a supercells of cubic XW_{26}O_{81}, where X=Nb,V and Re. The undoped material is an insulator, and although the slightly doped material is a metal, it is far from the Stoner criterion of magnetism. The conditions of a localized density-of-states which varies rapidly with the energy, resemble those of doped hexaborides. The virtual crystal approximation is used to vary the doping level. A small moment appears if the Fermi energy coincides with a large derivative of the DOS.