We have investigated electronic and magnetic properties of the pyrite-type CoS_2 using the linearized muffin-tin orbital (LMTO) 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 μL=0.06μB in the local spin density approximation (LSDA). The calculated ratio of the orbital to spin angular momenta <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≲1 eV, and so CoS_2 is possibly categorized as an itinerant ferromagnet. It is found that the observed electronic and magnetic behaviors of CoS_2 can be described better by the LSDA than by the LSDA + U.
@article{arxiv.cond-mat/0001028,
title = {Itinerant ferromagnetism in half-metallic CoS_2},
author = {S. K. Kwon and S. J. Youn and B. I. Min},
journal= {arXiv preprint arXiv:cond-mat/0001028},
year = {2009}
}