Half-metallic and Magnetic Properties of (001) Surfaces of KCaN2Compound in full-Heusler Structure

Abstract

The electronic and the magnetic properties of (001) surface of <TEX>$KCaN_2$</TEX> half-metallic compound with full-Heusler structure are studied with the use of a full-potential linearized augmented plane wave method. Two possible terminations of the surface are considered and only the one with N atoms in the topmost layer is found to retain the half-metallic properties of the bulk. The magnetic properties of N-terminated surface are enhanced compared with the properties of the bulk. The calculated magnetic moments on the N atoms in the <TEX>$KCaN_2$</TEX> are 1.26 <TEX>${\mu}_B$</TEX> in the bulk and 1.90 <TEX>${\mu}_B$</TEX> at the surface. The subsurface metal atoms are also slightly polarized. In the surface terminated with metal atoms, not only the half-metallicity is destroyed, but also the magnetic properties of the system are weakened.