ATOMIC-SCALE DETERMINATION OF MISFIT DISLOCATION LOOPS AT METAL-METALINTERFACES

The growth of one monolayer of Au on Ni(111) is shown to lead to an or dered array of misfit dislocation loops in the underlying Ni(111) surf ace. The signature of these loops is observed by scanning tunneling mi croscopy, and atomistic simulations are used to relate the observed su rface structure to that of the buried interface. The new interface str ucture is different from normal misfit dislocation structures in three respects: (i) it forms already during growth of a single Au monolayer , (ii) it forms in the substrate and not in the overlayer, and (iii) i t is controlled by the interface energy rather than by the strain in t he two phases.