Effect of local environment on nanoscale dynamics at electrochemical interfaces: anisotropic growth and dissolution in the presence of a step providing evidence for a schwoebel-ehrlich barrier at solid/liquid interfaces.

The dynamics of nanoscale islands in the vicinity of a monoatomic step on a metal electrode surface under potential control have been investigated by potential pulse perturbation time-resolved scanning tunneling microscopy (P3 TR-STM). As the metastable islands decay, a clear anisotropy develops in the spatial distribution of islands, relative to the monoatomic step. Islands appear to be stabilized above the step, while a denuded region develops below the step over a distance of about 100 nm. Vacancy islands are observed to be more stable than adatom islands. These results provide evidence for an electrochemical Schwoebel-Ehrlich barrier to diffusion of atoms across the step.