Abstract
In this study, the effect of vacancy formation on La-doped SrTiO3 was investigated by first-principles calculation. It was found that cation vacancy induces lattice expansion, while oxygen vacancy induces lattice shrinkage. These structural changes can be understood by the changes of coulomb interaction between charged vacancy and surrounding ions. In addition, substituted La was found to reduce the formation energy of cation vacancy. Therefore, it can be suggested that previously observed lattice expansion in La-doped SrTiO3 in air was attributed by the cation vacancy, while lattice shrinkage under reducing atmosphere was attributed by the oxygen vacancy. At the conference, comparison between calculation and experiment will be discussed.
