Spontaneous symmetry breaking of dislocation core in SrTiO3

Abstract

Dislocation endows intriguing properties in materials and attracted extensive interest, while its potential is far from being fully explored. Here, we use first-principles simulations to explore the property of an edge dislocation core in SrTiO3, an incipient ferroelectricity with a prototype perovskite structure. We discovered the spontaneous symmetry breaking in the dislocation, which is introduced by the atomic movement in the core and the Ti–O octahedron's distortion in the nearby unit cells. Next, we systematically investigate the coupling relationship between strain modes and ferroelectric atomic displacement modes based on group representation theory, and further proposed a model to quantificationally estimate the atomic configuration of SrTiO3 under complex strain conditions, which predicts the polarization near the dislocation decently.