Using molecular static simulations possible mechanisms of stress relaxation with misfit dislocation nucleation in strained hetero-epitaxial layers were studied. Two-dimensional models of atomic systems with Lennard-Jones type potential were considered. Combination of total energy minimization with spherical repulsion and nudged elastic band calculation permitted the study of possible transitions between an initial coherent interface state and a final state with a single dislocation. Different transition paths involving either successive relaxation of layers or concerted sliding along atomic rows were identified as possible mechanisms with low activation energies. The role of these mechanisms in hetero-epitaxial thin film growth and possible implementations in 3 dimensions were analyzed.

Mechanisms of Dislocation Nucleation in Strained Epitaxial Layers. O.Trushin, E.Granato, S.C.Ying, P.Salo, T.Ala-Nissila: Physica Status Solidi B, 2002, 232[1], 100-5