Density functional theory study of nitrogen-induced magnetism in rutile TiO2

We have investigated the structural, electronic, magnetic properties and chemical bonding of N-doped rutile TiO2 by a first-principles ultrasoft pseudopotential of the plane-wave within the density-functional theory (DFT). We find the polarized holes above the Fermi level by 1.058 eV, indicating that the magnetic coupling is mediated by the deep hole doping. The asymmetrical spin of N-2p states are mainly responsible for the origin of the ferromagnetism. The polarized holes from the N 2pπ and the Ti 3d (Eg+B2g) in D4hD4h induce the π bonding.