Electronic and magnetic properties of Ti2O3, Cr2O3, and Fe2O3 calculated by the screened exchange hybrid density functional

Abstract

The electronic and magnetic properties of the transition metal sesqui-oxides Cr2O3, Ti2O3, and Fe2O3 have been calculated using the screened exchange (sX) hybrid density functional. This functional is found to give a band structure, bandgap, and magnetic moment in better agreement with experiment than the local density approximation (LDA) or the LDA+U methods. Ti2O3 is found to be a spin-paired insulator with a bandgap of 0.22 eV in the Ti d orbitals. Cr2O3 in its anti-ferromagnetic phase is an intermediate charge transfer Mott–Hubbard insulator with an indirect bandgap of 3.31 eV. Fe2O3, with anti-ferromagnetic order, is found to be a wide bandgap charge transfer semiconductor with a 2.41 eV gap. Interestingly sX outperforms the HSE functional for the bandgaps of these oxides.