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 (P-3 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.