TEST OF THE PEIERLS-NABARRO MODEL FOR DISLOCATIONS IN SILICON

We show, using an atomistic model with a Stillinger-Weber potential (S WP), that in the absence of reconstruction, the basic assumption of th e Peierls-Nabarro (PN) model that the dislocation core is spread withi n the glide plane is verified for silicon. The Peierls stress (PS) obt ained from the two models are in quantitative agreement (approximate t o 0.3 mu), when restoring forces obtained from first principles genera lized 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 wa s found to be isotropic in the glide plane. Within the SWP model no ev idence of dissociation in the shuffle dislocations is found bur, glide sets do separate into two partials.