The minimum energy path and energy barriers for dislocation nucleation in a 2-dimensional atomistic model of strained epitaxial layers on a substrate with lattice misfit were studied numerically. Stress relaxation processes from coherent to incoherent states for different transition paths were determined by using a saddle-point search based upon a combination of repulsive potential minimization and the Nudged Elastic Band method. The minimum energy barrier leading to a final state with a single misfit dislocation nucleation was determined. A strong tensile-compressive asymmetry was observed. This asymmetry could be understood in terms of the qualitatively different transition paths for the tensile and compressive strains.

Minimum Energy Paths for Dislocation Nucleation in Strained Epitaxial Layers. O.Trushin, E.Granato, S.C.Ying, P.Salo, T.Ala-Nissila: Physical Review B, 2002, 65[24], 241408 (4pp)