ON ATOMIC DISREGISTRY, MISFIT ENERGY, AND THE PEIERLS STRESS OF A CRYSTALLINE DISLOCATION

A b s t r a c t Analytical determination of the Peierls stress required to move an edge dislocation in a crystalline lattice is studied from the combined atomistic and continuum elasticity points of view. Particular attention is given to the sinusoidal relationship between the shear stress and atomic disregistry across the glide plane, and the relationship between the dislocation width and the atomic interplanar separation across the glide plane. The analysis is based on the assumption that the dislocation core radius periodically varies during the glide of the dislocation between its consecutive equilibrium conflgurations. The resulting material parameters appearing in the expression for the lattice friction stress are related to those of a semi-discrete Peierls{Nabarro model and the corresponding calculation of the misflt energy based on either single or double-counting scheme.