Half-metallic to insulating behavior of rare-earth nitrides

The electronic structure of the rare-earth nitrides is studied systematically using the ab initio self-interaction corrected local-spin-density approximation. This approach allows both a localized description of the rare-earth f electrons and an itinerant description of the valence electrons. Localizing different numbers of f electrons on the rare-earth atom corresponds to different valencies, and the total energies can be compared, providing a first-principles description of valence. We show that these materials have a broad range of electronic properties including forming a different class of half-metallic magnets with high magnetic moments, and are strong candidates for applications in spin-filtering devices.