It was noted that, in Si and other materials having a high Peierls potential, dislocation motion took place via the nucleation and propagation of kink pairs. The rates of these unit processes were unknown functions of stress, temperature and interatomic interactions in the dislocation core. An attempt was made here to develop a quantitative physical description, of dislocation motion in Si, which was based upon an understanding of the core structure and the energetics of core mobility mechanisms. Atomistic simulations revealed multiple and complex kink mechanisms for dislocation translation. However, this complexity could be rationalized via the analysis, of a straight kink-free dislocation, which was based upon symmetry-breaking arguments. A further reduction was achieved by observing that the energetics of kink mechanisms were scaled by a single parameter: the energy required to break a bond in the core. In order to obtain accurate values for this energy, density functional calculations were performed that led to the conclusion that the low mobility of 30° dislocations resulted from its high bond-breaking energy. By using this knowledge concerning kink mechanisms, a kinetic Monte Carlo model was developed which made direct use of the atomistic data as input and thereby predicted the dislocation velocity at length and time scales which were accessible to experiment. This established a connection between atomistic aspects of the dislocation core, and the mobility of single dislocations.

Parameter-Free Modelling of Dislocation Motion: the Case of Silicon. V.V.Bulatov, J.F.Justo, W.Cai, S.Yip, A.S.Argon, T.Lenosky, M.De Koning, T.Diaz de la Rubia: Philosophical Magazine A, 2001, 81[5], 1257-81