Half-metallicity in Rh-doped TiO2 from ab initio calculations

First-principles calculations based on density functional theory (DFT) are performed to study the electronic structures and magnetic properties of Rh-doped TiO2 crystals. The hybridization between Rh-4d and O-2p results in Rh becoming ferromagnetic with a magnetic moment of about 1.0 μ B per supercell. The Rh-doped TiO2 system exhibits half-metallic ferromagnetism based both DFT and DFT + U. The strong ferromagnetic couplings between local magnetic moments can be attributed to both the p-d hybridization and double-exchange mechanisms, as well as superexchange interaction. These results suggest an alternative approach to achieve promising dilute magnetic semiconductors by doping non-magnetic transition metals in a TiO2 host.