Grain boundary stoichiometry and interactions with defects in SrTiO3

We examine the role that the atomic structure, both the terminating plane and the stoichiometry, of Σ3 twin boundaries in SrTiO3 has on the interaction of point defects using an interatomic potential. Both factors strongly influence defect interactions with the boundary, with interactions strongest for the non-stoichiometric boundary. These results are confirmed with density functional theory. We conclude that boundary atomic structure must be accounted for when understanding the properties of oxides with a large fraction of grain boundaries.