Electronic structure of alkali-metal fluorides, oxides and nitrides: Density-functional calculations including self-interaction corrections

Baumeier B, Krüger P, Pollmann J, Vajenine G

Zusammenfassung

The recently synthesized compound Na3N has experimentally been shown to be semiconducting much in contrast to the outcome of standard density-functional theory calculations which find Na3N to be metallic. To address this obvious contradiction, we have systematically investigated the electronic structure of Na3N by density-functional calculations employing self-interaction-corrected pseudopotentials which have been shown before to yield results in much better agreement with experiment than standard local-density calculations. To assess the usefulness of such pseudopotentials for a broader class of related materials, we have carried out, in addition, a comparative ab initio study of the electronic structure of the nine alkali-metal fluorides MF, oxides M2O, and nitrides M3N with M=Li, Na, and K. We arrive at valence and conduction bands that are in good agreement with the restricted results available in the literature from calculations going beyond the local-density approximation and from experiment. In particular, Na3N turns out to be clearly semiconducting, as observed in experiment.