Electronic structure and properties of magnesium oxide

Abstract

We have carried out an ab initio study of the electronic structure and properties of magnesium oxide. The self-consistent charge density in the crystal is obtained by solving the Adams-Gilbert local-orbitals equations. The Fock operator is then constructed with nonlocal exchange and the energy bands are computed. These bands are then corrected for correlation effects. Long-range contributions are calculated by means of the electronic-polaron model. Short-range contributions are found to be large as predicted recently by the authors for fluorides, oxides, and nitrides in general. The final energy bands are in agreement with optical and x-ray data for the gaps and other transition energies. We predict an indirect minimum gap in MgO. The structure in the uv optical spectra is reproduced by our joint density of states and ${\ensuremath{\epsilon}}_{2}(\ensuremath{\omega})$ calculation. We compare our results with previous theoretical studies in the empirical-pseudopotential scheme and the Hartree-Fock-Slater approximation. MgO is the first II-VI compound and the first oxide to be treated in the Hartree-Fock scheme.