Electronic band structure of Nb doped SrTiO3 from first principles calculation

The effect of Nb doping of oxide perovskite SrTiO3 on the electronic properties is studied by semirelativistic linear muffin-tin orbital method with atomic sphere approximation (LMTO-ASA). The computational lattice constants are in good agreement with experimental data. The Fermi level of SrTi1-xNbxO3 with x≥0.125 moves into the bottom of conduction band and the system shows metallic behavior. Due to the appearance of the charge impurity potential from Nb doping, there is a large distortion on the top of valence band for SrTi1-xNbxO3 with 0.125≤x≤0.25. The distortion becomes weak with x=0.5 because of the carriers screening effect. Our computational results also show that the Nb doping effect on the electronic structure of SrTi1-xNbxO3 cannot be described within a simple rigid-band model well