First Principle Study on the Influence of Sr/Ti Ratio on the Atomic Structure and Dislocation Behavior of SrTiO ₃

Using the first principle method, we investigate the influence of Sr/Ti ratio on the atomic structure and dislocation behavior of Sr n+1 Ti n O 3n+1 (Ruddlesden—Popper phase) and Sr n Ti n+1 O 3n+2 (Magnéli phase). A linear lattice expansion versus the Sr/Ti ratio exhibits in the Ruddlesden—Popper and Magnéli phases. The Ruddlesden—Popper phase has lower formation energy and superior structural stability than the Magnéli phase. The two phases show different dislocation behaviors and it is found that a possibly preferred slip system 〈110〉 {110} emerges in the two phases, and the dislocations are more likely to dissociate into partial dislocations in Magnéli phases.