THE GENERALIZED PEIERLS-NABARRO MODEL

In the original Peierls-Nabarro model the core structure of a dislocat ion is determined as the solution of an integrodifferential equation. This equation describes the balance between the forces resulting from the deformation of two elastic half-spaces and from a one-dimensional periodic lattice potential acting across the glide plane. A method is described here which allows the core structure and core energy to be o btained for a straight dislocation with arbitrary Burgers vector in an arbitrary glide plane in a crystal of arbitrary anisotropy, for which the displacement potential is represented by a two-dimensional Fourie r series. This is accomplished by describing the internal displacement s by appropriate trial functions with a set of free parameters whose v alue is then determined by minimizing the total energy. The method is applied to obtain the core configuration of a screw dislocation dissoc iated in a {111} plane of a f.c.c. lattice.