TEST OF THE PEIERLS-NABARRO MODEL FOR DISLOCATIONS IN SILICON

We show, using an atomistic model with a Stillinger-Weber potential (SWP), that in the absence of reconstruction, the basic assumption of the Peierls-Nabarro (PN) model that the dislocation core is spread within the glide plane is verified for silicon. The Peierls stress (PS) obtained from the two models are in quantitative agreement (approximate to 0.3 mu), when restoring forces obtained from first principles generalized stacking-fault energy surfaces are used in the PN model [B. Joos, Q. Ren, and M. S. Duesbery, Phys. Rev. B 50, 5890 (1994)]. The PS was found to be isotropic in the glide plane. Within the SWP model no evidence of dissociation in the shuffle dislocations is found bur, glide sets do separate into two partials.