Structural, electronic and magnetic properties of iron carbonitride FeC 1− x N x compounds from first principles

Abstract The results of first principles calculations as based on density functional theory investigating the impact of nitrogen substitution for carbon on the structural, electronic and magnetic properties of ordered iron carbonitrides FeC 1− x N x ( x = 0, 0.25, 0.5, 0.75, and 1) in the rocksalt- and zincblende-type structures are reported. In the former, nitrogen insertion causes increase of the cell volume and the ferromagnetic moment, whereas the latter displays a decreasing volume without magnetic ordering (except for the case x = 0.25). While for all compositions the zincblende-derived structures form the ground state, the rocksalt-type structures are expected to form at increased pressures. Site-, orbital-, and spin-resolved densities of states indicate covalent bonding with distinct splitting of the Fe 3 d states into their e g and t 2 g manifolds. Interestingly, electronic correlations as included within the GGA+ U approach cause distinct changes of the partial DOS for the rocksalt-derived structures but have almost no effect for the zincblende-type structures.