The interaction between 2 partial 90 edge dislocations was studied by means of atomic-scale simulations, using the effective-medium tight-binding method. A wide (up to 3nm) separation between the 2 dislocations, which was comparable to experimentally observed values, was achieved by using a solution to the tight-binding Hamiltonian which scaled linearly with the number of atoms. The partial edge dislocation was found to be very accurately described by the Peierls-Nabarro dislocation model, with generalized stacking-fault restoring forces; as reflected both by the interaction energy and by the displacement field. An asymmetrical core reconstruction provided 4-fold coordination, and made the Si behave elastically down to atomic distances.

L.B.Hansen, K.Stokbro, B.I.Lundqvist, K.W.Jacobsen, D.M.Deaven: Physical Review Letters, 1995, 75[24], 4444-7