Structural instability of epitaxial zinc-blende vanadium pnictides and chalcogenides for half-metallic ferromagnets

Abstract

We present a first-principles study of the criteria governing the electronic and structural stability of epitaxial, half-metallic ferromagnetic materials with zinc-blende structure. Upon their application to vanadium pnictides and chalcogenides, we find that the criteria for structural stability are crucial when the optimal match pattern of an epitaxial film with the substrate is considered. Our study shows that thick zinc-blende epitaxial films are difficult to obtain by coherent epitaxial growth for vanadium pnictides and chalcogenides. We suggest that more attention needs to be paid to spin polarized ultrathin films (instead of the thick films) as high spin injection materials.