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

Abstract

Using the first principle method, we investigate the influence of Sr/Ti ratio on the atomic structure and dislocation behavior of Sr𝑛+1Ti𝑛O3𝑛+1(Ruddlesden-Popper phase) and Sr𝑛Ti𝑛+1O3𝑛+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.