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 apply ing a transition path technique. The minimum energy path (MEP) in a high di mensional configuration-space from one stable configuration to the adjacent one is calculated as a function of applied stress. From the energy profile s along the MEP, the applied stress dependence of the activation energy (De ltaH - tau relation) and the Peierls stress are obtained. The Peierls poten tial can reasonably be defined, when the position of the dislocation is det ermined along the MEP, taking account of the atomic displacements and the e nergy 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 Delt aH - tau relation obtained directly by the transition path calculation. (C) 2001 Elsevier Science B.V. Ail rights reserved.