The effects of Ni on structural and electronic properties of BaTiO3 ceramic

The theoretical effects of Ni on structural and electronic properties of BaTiO3 ceramic have been studied using full potential-linearized augmented plane wave (FP-LAPW) method in the framework of the density functional theory (DFT) with the generalized gradient approximation (GGA). The result of electronic structure shows a direct band gap of 2eV at the Γ point in the Brillouin zone. The results of calculation show that the chemical character of the lower valence band is mainly O-2s in nature while the upper valence band is predominantly O-2p in nature with a small admixture of Ti and Ni. The bottom of the conduction band is mainly composed of Ti-3d states with some mixture of Ba-5s state. We find also a notable contribution of O-2p states in the lower part of the conduction band. This points out to the hybridization effect between Ti-3d and O-2p orbital while the basic contribution Ni in conduction band up is eg. It appears also that the Ba–O bond is typically ionic while the Ti–O bond has a strong covalent character.