Nucleation of trapezoidal kink pairs on a Peierls potential

Abstract

The activation energy ΔH∗ for forming a kink pair of trapezoidal shape in a dislocation in a Peierls potential is calculated by considering the long-range elastic interaction between the dislocation segments. The shapes and energies obtained in this three-parameter model closely resemble those obtained from the continuous line-tension approximation, except at low stresses where ΔH∗ is well approximated by a square-root-dependence on the stress. If the potential is smooth, the stress dependence of the activation energy is also smooth. For a camel-hump potential, with an intermediate minimum, a discontinuity appears in the stress-dependence.