Half-metallicity of bulk and (111) surface for full-Heusler alloy Co2VAl: A density functional study

Abstract

Abstract Motivated by the recent experimental synthesis of the bulk and thin films for full-Heusler alloy Co 2 VAl, we investigate the structural, electronic and magnetic properties of the bulk Co 2 VAl and its (1 1 1) surfaces based on the density functional theory. The half-metallic ferromagnetism with the magnetic moment of 2.00 μ B per formula unit is confirmed in the bulk Co 2 VAl with L 2 1 structure. For the four possible (1 1 1) surfaces, it is shown from the present DOS that the bulk half-metallicity is preserved at V- and Al-terminated surfaces but destroyed by some surface states at Co–V- and Co–Al-terminated surfaces. We also find that the atomic magnetic moments at the (1 1 1) surfaces are greatly different from the bulk values due to the effect of symmetry breaking at the surface. Moreover, the structure relaxation indicates that Al- and V-terminated surfaces are more favorable to the applications of spintronic devices.