Peierls stress for 〈110〉{001} mixed dislocation in SrTiO3 within framework of constrained path approximation

Abstract

The core structure of 〈110〉{001} mixed dislocation in perovskite SrTiO3 is investigated with the modified two-dimensional Peierls–Nabarro dislocation equation considering the discreteness effect of crystals. The results show that the core structure of mixed dislocation is independent of the unstable energy in the 〈100〉 direction, but closely related to the unstable energy in the 〈110〉 direction which is the direction of total Burgers vector of mixed dislocation. Furthermore, the ratio of edge displacement to screw one nearly equals to the tangent of dislocation angle for different unstable energies in the 〈110〉 direction. Thus, the constrained path approximation is effective for the 〈110〉{001} mixed dislocation in SrTiO3 and two-dimensional equation can degenerate into one-dimensional equation that is only related to the dislocation angle. The Peierls stress for 〈110〉{001} dislocations can be expediently obtained with the one-dimensional equation and the predictive values for edge, mixed and screw dislocations are 0.17, 0.22 and 0.46 GPa, respectively.