Atomic-Scale Determination of Misfit Dislocation Loops at Metal-Metal Interfaces

The growth of one monolayer of Au on Ni(111) is shown to lead to an ordered array of misfit dislocation loops in the underlying Ni(111) surface. The signature of these loops is observed by scanning tunneling microscopy, and atomistic simulations are used to relate the observed surface structure to that of the buried interface. The new interface structure 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) it is controlled by the interface energy rather than by the strain in the two phases.