We study numerically the minimum energy path and energy barriers for dislocation nucleation in a two-dimensional atomistic model of strained epitaxial layers on a substrate with lattice misfit. Stress relaxation processes from coherent to incoherent states for different transition paths are determined using saddle point search based on 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 is determined. A strong tensile-compressive asymmetry is observed. This asymmetry can be understood in terms of the qualitatively different transition paths for the tensile and compressive strains.
@article{arxiv.cond-mat/0205620,
title = {Minimum energy paths for dislocation nucleation in strained epitaxial layers},
author = {O. Trushin and E. Granato and S. C. Ying and P. Salo and T. Ala-Nissila},
journal= {arXiv preprint arXiv:cond-mat/0205620},
year = {2009}
}
Comments
4 pages + 3 figs, to appear in Phys. Rev. B, Rap. Comm