Half metallic antiferromagnetic behavior in doped TiO2 rutile with double impurities (Os, Mo) from ab initio calculations

Electronic and magnetic calculations were based on density functional theory within the generalized gradient approximation for II-VI compound semiconductor TiO2 doped with single impurity Os and Mo; these compounds are half-metallic ferromagnets in their ground state with a total magnetic moment of 2μB for both systems. Then, doping TiO2 with double impurities (Os, Mo) was performed. As a result, Ti1 − 2xOsxMoxO2 with x = 0.065 is a half-metallic antiferromagnet with 100% spin polarization of the conduction electrons crossing the Fermi level, without showing a net magnetization. Moreover, the Ti14OsMoO32 compound is stable energetically than Ti1 − xMoxO2 and Ti1 − xOsxO2. The antiferromagnetic interaction in the Ti1 − 2xOsxMoxO2 system is attributed to the double exchange mechanism, and the latter could also be the origin of their half-metallic behavior.