Sub-monolayer films of Ag on Pt(111) exhibited parallel partial dislocations which were separated by narrow hexagonal close-packed domains, and much wider face-centered cubic domains. The large difference in width was atypical of strained metal overlayers on close-packed substrates. Calculations were made of the relative domain widths by using a 2-dimensional Frenkel-Kontorova model. The possible effects of dislocations upon equilibrium island shape were examined, and calculations were made of the energies of stable and metastable dislocation structures as a function of island size. The experimental results were explained in terms of proximity to the incommensurate-commensurate phase transition.

Dislocation Structures of Submonolayer Films near the Commensurate-Incommensurate Phase Transition: Ag on Pt(111). J.C.Hamilton, R.Stumpf, K.Bromann, M.Giovannini, K.Kern, H.Brune: Physical Review Letters, 1999, 82[22], 4488-91