Ab-initio study of half-metallic ferromagnetism in Co/Ni substituted Li2X (X=S, Se, Te) compounds

Electronic structure and half-metallic ferromagnetism of Co/Ni substituted Li2X (X=S, Se, Te) have been studied using the ab-initio method. Appropriately constructed supercells along with the full structural optimization of these cells are used for studying the effect of one and two Co/Ni ions substitution on the magnetism and electronic properties of these compounds. Our results reveal that the Co/Ni ions can induce ferromagnetic ground state in these compounds. Both one and two Co/Ni ions substituted Li2X (X=S, Se, Te) exhibit half-metallic behavior (except for Co substituted Te systems), thereby exhibiting 100% spin polarization. We further observed that the electron correlation effects on these materials do not affect the half-metallic ferromagnetism of these compounds. Curie temperature (Tc) of these compounds is also estimated. The Co/Ni substituted Li2X (X=S, Se, Te) compounds are thus an interesting class of half-metallic materials that deserve further studies.