Half-metallic ferromagnetism in transition metal pnictides and chalcogenides with wurtzite structure

Using an accurate full-potential density-functional method we explore systematically all the $3d$ transition metal pnictides and chalcogenides with wurtzite structure in order to find half-metallic ferromagnets which can be fabricated as thin films with thickness large enough for real spintronic applications. Nine of the wurtzite phases, MnSb, CrAs, CrSb, VAs, VSb, CrSe, CrTe, VSe, and VTe, are found to be robust half-metallic ferromagnets. They have very large half-metallic gaps (0.23--0.97 eV) and quite large bulk moduli (42--71 GPa). Most of them are quite low (down to 0.31 eV per formula unit) in total energy with respect to the corresponding ground-state phases, and therefore at least some of them would be grown epitaxially on appropriate substrates in the form of films thick enough. Since being compatible with the III-V and II-VI semiconductors, these half-metallic ferromagnetic phases, when realized experimentally, would be useful in spintronic and other applications.