ATOMIC MODES OF DISLOCATION MOBILITY IN SILICON

Mechanisms of partial dislocation mobility in the {111} glide system o f silicon have been studied in full atomistic detail by applying novel effective relaxation and sampling algorithms in conjunction with the Stillinger-Weber empirical interatomic potential and simulation models of up to 90000 atoms. Low-energy pathways are determined for the gene ration, annihilation and motion of in-core defects of the 30 degrees-p artial dislocation, specifically, the individual left and right compon ents of a double-kink, an antiphase defect (APD), and various kink-APD complexes. It is shown that the underlying mechanisms in these defect reactions fall into three distinct categories, characterized by the p rocesses of bond-breaking, bond switching, and bond exchange, respecti vely. The quantitative results reveal a strong left-right asymmetry in the kinetics of kink propagation and a strong APD-kink binding; these have not been recognized previously and therefore hold implications f or further experiments. The present work also demonstrates the feasibi lity of the atomistic approach to modelling the kinetic processes unde rlying dislocation mobility in crystals with high Peierls barriers.