ATOMISTIC MODELING OF CRYSTAL-DEFECT MOBILITY AND INTERACTIONS

A novel and efficient simulation method for determining the saddle-poi nt configuration of a localized structural defect in a crystalline lat tice is developed and applied to elucidate the dominant mechanisms of dislocation and self-interstitial mobility and of dislocation intersec tions. The method is able to locate the migration path between two pre scribed defect configurations, and involves sampling a discretized pat h connecting two neighboring potential energy minima. Using the Stilli nger-Weber interatomic potential for silicon, activation energies are found for the displacement of the 30 degrees-partial dislocation (glid e set) via the double-kink mechanism and the migration of a self-inter stitial via a jump-rotation process. In the intersections of straight partial dislocations, jog and kink formations are observed and consequ ences of the strong core reconstruction on the energetics of intersect ion are examined.