Transition path of a lattice dislocation in a high dimensional configuration space

Motion of a dislocation in a simple model lattice has been studied by applying a transition path technique. The minimum energy path (MEP) in a high dimensional configuration-space from one stable configuration to the adjacent one is calculated as a function of applied stress. From the energy profiles along the MEP, the applied stress dependence of the activation energy (ΔH−τ relation) and the Peierls stress are obtained. The Peierls potential can reasonably be defined, when the position of the dislocation is determined along the MEP, taking account of the atomic displacements and the energy inside the dislocation core of radius 3b. The conventional scheme for determining the stress dependence of the activation energy, which assumes a Peierls potential with the work done term subtracted, reproduces the ΔH−τ relation obtained directly by the transition path calculation.