Crystal, electronic and magnetic structure of Co and Ag doped rutile TiO_2 from first-principles calculations

摘要

The crystal structure, electronic structure and ferromagnetic properties of the transition metals M (where M=Co, Ag) doped rutile TiO_2 are studied by using first-principles calculations based on the density functional theory (DFT) and projector augmented wave (PAW) pseudo-potentials (PP) method. In the doped system M_2Ti_(14)O_(32), the two doping atoms tend to align along c axis in the stablest configuration state. When M represents Co atom, the ferromagnetic state is favorable with magnetic moments of 0.99μB per Co atom, while Ag_2Ti_(14)O_(32) has no magnetic moment. Doping atoms induce new energy level, which reduces band gap, decreases Fermi energy level and thus considerably affects the optical absorption and photocatalytic activities of TiO_2 under visible light irradiation.