LINEAR DECAY OF ISLANDS ON METAL-SURFACES

Scanning-tunneling-microscope studies of mass flow on (111) Au have sh own that the rate of decay of the area of monolayer islands is linear in time. We demonstrate by Monte Carlo simulation that a proper accoun ting of the detachment and reattachment rates of kink site atoms produ ces a linear decay. In our simulation, adatoms emitted from kink sites on mesa edges execute an unbiased random walk and may reattach to the home mesa or be absorbed by an outer ledge, possibly after several re flections from the step down at the outer ledge. The linear decay of m esa areas is found to be rather insensitive to variations in the proba bility of reflection from the outer ledge.