Ferromagnetic Half-Metal Cyanamides Cr(NCN)(2) Predicted from First Principles Investigation

The stability, physical properties, and electronic structures of Cr(NCN)(2) were studied using density functional theory with explicit electronic correlation (GGA+U). The calculated results indicate that Cr(NCN)(2) is a ferromagnetic and half-metal, both thermodynamically and elastically stable. A comparative study on the electronic structures of Cr(NCN)(2) and CrO(2) shows that the Cr atoms in both compounds are in one crystallographically equivalent site, with an ideal 4+ valence state. In CrO(2), the Cr atoms at the corner and center sites have different magnetic moments and orbital occupancies, moreover, there is a large difference between the intra- (12.1 meV) and inter-chain (31.2 meV) magnetic couplings, which is significantly weakened by C atoms in Cr(NCN)(2).