Interaction between two partial 90 degrees edge dislocations is studied with atomic-scale simulations using the effective-medium tight-binding method. A large separation between the two dislocations (up to 30 Angstrom), comparable to experimental values, is achieved with a solution of the tight-binding Hamiltonian that scales linearly with the number of atoms. The partial edge dislocation is found to be very accurately described by the Peierls-Nabarro dislocation model, with generalized stacking-fault restoring forces, as reflected both in the interaction energy and in the displacement field. An asymmetric core reconstruction provides fourfold coordination, making Si behave elastically down to atomic distances.
Bibliographical noteCopyright (1995) American Physical Society.