First-principle study on the magnetic properties of six potential half-metallic ferromagnets: C-doped alkaline-earth chalcogenides

Six half-metallic ferromagnets with NaCl structure, X4CY3 (X=Mg, Ca, and Sr and Y=O and S) are predicted by the first principle calculations based on the density functional theory. The supercell magnetic moments of these ferromagnets are all integer 2.0μB, which are one of important characters of half-metallic ferromagnets. Our calculations indicate that X4CY3 have wide spin gap and potentially have high Curie temperature. C-doping results in the spin-polarization and half-metallicity of these alkaline-earth chalcogenides. The main reason is that there are sp hybridized orbitals in X4CY3, and two outer-shell s-electrons of alkaline-earth ions enter into sp hybridized orbitals in parallel.