Formation of interface states on a half-metal surface

Abstract

The surface and interface properties of half-metallic materials are potentially of crucial importance to their proposed spin-electronic device applications. In this letter, we investigate the influence of metallic overlayers of Sb on the pair of minority-spin surface electronic states previously reported on NiMnSb {0 0 1} . Through first-principles density functional theory, we find that monolayer and half-monolayer coverages of Sb interact with the surface states in distinctly different ways. Furthermore, as the coverage of Sb is increased beyond a monolayer, we find that the surface states transform smoothly into interface states in which coupling to the bulk of the overlayer is minimal and predominantly confined to the edge of the Brillouin zone.