First-principles prediction of half-metallic ferromagnetism in five transition-metal chalcogenides: The case of rocksalt structure.

Motivated by the experimental synthesis of bulk rocksalt MnS, MnSe, and MnTe, we show with first-principles calculations that among all transition-metal pnictides and chalcogenides with rocksalt structure CrTe, VPo, and CrPo are truly half-metallic ferromagnets, and both VTe and CrSe exhibit nearly half-metallicity. Importantly, for these five half-metallic compounds, the rocksalt phase is energetically more stable than the zinc-blende and wurtzite ones, and the total energy differences between the rocksalt and ground-state NiAs phases are very small (0.06-0.43 eV/f.u.) and comparable with that of experimental MnTe (0.24 eV/f.u.), thus like rocksalt manganese chalcogenides, these five rocksalt half-metals would be realized in the form of bulk or at list thin films for spintronic applications. In addition, we study the (111) surface properties of rocksalt CrPo and find both Cr- and Po-terminated (111) surfaces retain the bulk half-metallicity. We also reveal that the spin-orbit coupling has very weak effect on the half-metallicity of rocksalt CrSe, VTe, and CrTe, and the spin polarizations are still high for rocksalt VPo and CrPo although the spin-orbit coupling affects greatly their half-metallicities. [ABSTRACT FROM AUTHOR]