The electronic structure of Ni doped rutile TiO2

Abstract

The electronic structure of 6.25% Ni doped rutile titanium dioxide (Ni/TiO2) was investigated by ab initio ultrasoft pseudopotential plane wave method based on density functional theory. When a Ni atom was substituted for a Ti site of TiO2 lattice, two additional unoccupied 3d states appeared as defect states in band gap, and occupied 3d states were hybridized with oxygen 2p states. From the calculation of band decomposed charge density and density of states, it was found that the lower defect state (D-1), a Ni 3d-orbital, was hybridized with unoccupied oxygen 2p states and the higher one (D-2), localized 3d-orbital of Ni, was located at the middle of band gap.