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 SrTiO 3 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 SrTiO 3 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.

On the Properties of Shuffle Dislocation in BC5: Core Structure and Peierls Barrier and Stress

“…The discrete effect is represented by a term proportional to the second-order derivative of displacement. It is found that the agreement between theoretical prediction given by improved P-N theory and the numerical results can be remarkably improved [20][21][22][23][24][25][26][27][28] . In this paper, the core structures of shuffle dislocations in BC5 have been studied by the improved P-N equation and the Peierls barriers and stresses have been evaluated with considering the contribution from strain energy.…”

On the core width and Peierls stress of bubble rafts dislocations within the framework of modified Peierls-Nabarro model

“…However, the GSF energy of bubble rafts is hard to obtain and the restoring force law for different radii is derived directly based on the interaction between bubbles within the Peierls cut-glue scheme [8]. As described above, the expression for the restoring force law for bubble rafts is complex and the dislocation equation cannot be solved by variational method, although it is an effective method to solve the integro-differential dislocation equation [20,21]. In this paper, Foreman's method is applied to solve the modified P-N dislocation equation to determine the dislocation core structure in bubble rafts.…”