Static and dynamic simulations were used to study the thermally activated motion of dislocations. The two-dimensional Frenkel-Kontorova model was used. The main object was to permit  the simulation of dislocation dynamics over long periods (about 600ns) and thus access large ranges of applied stress and temperature. The kink-pair nucleation rates, deduced from dynamic simulations, were studied as a function of the ratio of the kink-pair activation enthalpy to the thermal energy. The former was found from static simulations, based upon the elastic nudged-band method. It was shown that the dislocation motion was composed of two regimes. These were a low-temperature regime, where the nucleation rate obeyed a thermally activated exponential law, and a high-temperature regime where the motion was slower than that expected on the basis of the low-temperature exponential law. A correlation was found between successive dislocation jumps. This arose from the dynamics of the internal modes of the dislocation, and impeded high-frequency nucleation events.

Kink-Pair Nucleation on Dislocations under Stress in the Two-Dimensional Frenkel-Kontorova Model. D.Rodney, L.Proville: Physical Review B, 2008, 78[10], 104115