An efficient simulation method was developed for determining the saddle-point configuration of a localized structural defect in a crystalline lattice, and was used to predict the predominant mechanisms of dislocation and self-interstitial mobility, and of dislocation intersection. The method could identify the migration path between 2 prescribed defect configurations. This involved the sampling of a discretized path which connected 2 neighboring potential-energy minima. By using the Stillinger-Weber atomic potential for Si, activation energies were found for the displacement of the 30º partial dislocation (glide set) via the double-kink mechanism, and the migration of a self-interstitial via a jump-rotation process. Jog and kink formation was observed during the intersection of straight dislocations, and the effect of core reconstruction upon the energetics of intersection was considered.

Atomistic Modelling of Crystal-Defect Mobility and Interactions. V.Bulatov, M.Nastar, J.Justo, S.Yip: Nuclear Instruments & Methods in Physics Research B, 1997, 121[1-4], 251-6