Half-metallic ferromagnetism of chalcopyrite ZnCrAs2: A first-principles prediction

Using the first-principles density functional method, we predict the half-metallic ferromagnetism of ZnCrAs2 in chalcopyrite structure with a magnetic moment of 2.0 mu(B) per formula unit. The band structures show the spin-up electrons are metallic, but the spin-down bands have a gap of 1.01 eV, and the energy gap between the top of valence band and the Fermi level is 0.52 eV. Based on the Heisenberg model, the magnetic exchange constants between Cr-Cr interactions for the first three nearest-neighbors were obtained, all three have the ferromagnetic character. From the estimate of mean-field approximation, the chalcopyrite ZnCrAs2 is a possible room-temperature ferromagnet. (C) 2011 American Institute of Physics. [doi:10.1063/1.3530728]