Itinerant ferromagnetism in half-metallic CoS2

Abstract

We have investigated electronic and magnetic properties of the pyrite-type CoS2 using the linearized muffin-tin orbital band method. We have obtained the ferromagnetic ground state with nearly half-metallic nature. The half-metallic stability is studied by using the fixed spin moment method. The non-negligible orbital magnetic moment of Co 3d electrons is obtained as mu(L) = 0.06 mu(B) in the local spin-density approximation (LSDA). The calculated ratio of the orbital to spin angular moments L-Z/S-Z = 0.15 is consistent with experiment. The effect of the Coulomb correlation between Co 3d electrons is also explored with the LSDA + U method. The Coulomb correlation at Co sites is not so large, U less than or similar to 1 eV, and so CoS2 is possibly categorized as an itinerant ferromagnet. It is found that the observed electronic and magnetic behaviors of CoS2 can be described better by the LSDA than by the LSDA + U.