Dislocation velocity and mobility were studied via molecular dynamics simulation for a 60º dislocation dipole in Si crystal. The atomic interactions were described using the Stillinger–Weber potential and the external stress was applied by means of the Parrinello–Rahman algorithm. It was found that the dislocation begins to move when the applied stress was larger than the Peierls stress, and the calculated Peierls stress decreases as the temperature increases, which was in agreement with the Peierls–Nabarro model. The dislocation velocity at relatively low temperature was insensitive to variation of temperature. In fact, the velocity increases monotonically as the stress increases, and eventually approaches its plateau velocity which was about 2900m/s. At higher temperature, however, the velocity no longer increases monotonically as the stress increases and the plateau velocity decreases as the temperature increases. In general, the dislocation velocity decreases as the temperature increases, which was consistent with the phonon drag model.

Atomistic Simulation of the 60º Dislocation Mobility in Silicon Crystal. C.X.Li, Q.Y.Meng, G.Li, L.J.Yang: Superlattices and Microstructures, 2006, 40[2], 113-8