Electronic and magnetic properties of V-doped anataseTiO2from first principles

We report a first-principles study on the geometric, electronic, and magnetic properties of V-doped anatase $\mathrm{Ti}{\mathrm{O}}_{2}$. The $\mathrm{DFT}+U$ (Hubbard coefficient) approach predicts semiconductor band structures for ${\mathrm{Ti}}_{1\ensuremath{-}x}{\mathrm{V}}_{x}{\mathrm{O}}_{2}$ ($x=6.25%$ and 12.5%), in good agreement with the poor conductivity of samples, while the standard calculation within generalized gradient approximation fails. Theoretical results show that V atoms tend to stay close and result in strong ferromagnetism through superexchange interactions. Oxygen vacancy induced magnetic polaron could produce long-range ferromagnetic interaction between largely separated magnetic impurities. The experimentally observed ferromagnetism in V-doped anatase $\mathrm{Ti}{\mathrm{O}}_{2}$ at room temperature may originate from a combination of short-range superexchange coupling and long-range bound magnetic polaron percolation.