Threshold strain required for a thermally activated dislocation nucleation from a Ni surface step was measured using an atomistic-based reaction pathway analysis. It was shown that the saddle-point configuration and the stress-dependent activation energy were strongly influenced by the presence of a surface step. The results provide insight into the previous experimental findings concerning the mechanism on a coherency loss at the Ni/Cu(001) interface. It was concluded that the coherency strain caused by a lattice mismatch between Ni and Cu does not yield a sufficient driving force for the dislocation nucleation.

Reaction Pathway Analysis for Dislocation Nucleation from a Ni Surface Step. S.Hara, S.Izumi, S.Sakai: Journal of Applied Physics, 2009, 106[9], 093507