Atomic and electronic structures of Mg-doped perfect SrTiO3 and crystals containing oxygen vacancies from first principles

The electronic properties of Mg-doped perfect SrTiO3 and crystals containing oxygen vacancies systems are investigated by first principles calculation. Dopant formation energy results show that the Mg atoms preferentially enter the Sr site in SrTiO3. Substitution of Ti by Mg brings some acceptor levels, which introduces the p-type conductivity of SrTiO3. Creation of oxygen vacancies in SrTiO3 introduces donor levels, which can contribute to the n-type conductivity. In SrTiO3 containing oxygen vacancies system, a self-compensation effect will occur when Ti is substituted by Mg, and the system undergoes n-type to p-type transition.