Electronic structure and optical properties of Nb-doped anatase TiO2

The electronic structure and optical properties of pure and Nb-doped TiO2 with anatase structure were calculated using local-density approximation based on the density-functional theory. For the undoped TiO2, the Fermi level locates in the band gap between the conduction band and valence band, while it moves into the conduction band and shows metal-like characteristic after Nb atom was introduced into the TiO2 supercell. The optical absorption coefficients for both compounds are very small in the visible light range. Our calculations provide electronic structure evidence that the Nb-doped anatase TiO2 is a new type transparent conducing metal. (c) 2008 American Institute of Physics.