It was demonstrated that a saddle-point search method could be used to study dislocation mobility in a covalent material. Repeated saddle-point searches were carried out by using the minimum mode-following algorithm and dimer method in combination with several empirical potential functions for silicon, in order to determine the mechanisms required for the creation and migration of kinks on a non-dissociated screw dislocation in a silicon crystal. For the environment-dependent interatomic potential, three possible kink migration processes were identified: with activation energies of 0.17, 0.25 and 0.33eV. The Lenosky potential gave a single low-energy migration mechanism, with an activation energy of 0.07eV; in good agreement with density functional theory results. The kink formation mechanism determined using this potential had an activation barrier of 1.2eV.

Finding Mechanism of Transitions in Complex Systems: Formation and Migration of Dislocation Kinks in a Silicon Crystal. A.Pedersen, L.Pizzagalli, H.Jónsson: Journal of Physics - Condensed Matter, 2009, 21[8], 084210