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 <f>SrTi1−xNbxO3</f> with <f>x&ges;0.125</f> 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 <f>SrTi1−xNbxO3</f> with <f>0.125&les;x&les;0.25</f>. The distortion becomes weak with <f>x=0.5</f> because of the carriers screening effect. Our computational results also show that the Nb doping effect on the electronic structure of <f>SrTi1−xNbxO3</f> cannot be described within a simple rigid-band model well. [Copyright &y& Elsevier]