Bandwidth controlled half-metallicity in a ferromagnetic metal: ab initio calculations

Abstract

We report the observation of the emergence of a half-metallic phase in a ferromagnetic metal, SrRuO₃, via Ti substitution at the Ru sites employing state-of-the-art ab initio calculations. Ti⁴⁺ (d⁰ electronic configuration) substitution is manifested in the form of valence-band narrowing and enhancement of the local moment of the otherwise highly extended 4d electrons. The energy gap between t_2g and e_g bands gradually increases with the increase in x in SrRu_1-xTi_xO₃ and becomes larger than 2 eV at x=0.875. Subsequently, a gap appears at the Fermi level, ε_F, in the up-spin density of states, while the down-spin states contribute at ε_F characterizing the system as a half-metallic ferromagnet. These results, thus, demonstrate a way to engineer metallicity in a ferromagnet leading to a half-metallic behavior.