Transition from One-Dimensional to Two-Dimensional Island Decay on an Anisotropic Surface

Abstract
We have investigated the decay of two-dimensional islands on the anisotropic Ag(110) surface using variable temperature scanning tunneling microscopy. Contrary to predictions from traditional Ostwald ripening theory, a quasi-one-dimensional decay mode is observed at low temperatures, 175–220 K. A surprisingly sharp transition to the quasi-two-dimensional decay mode is observed around 220 K. This transition is accompanied by a fast equilibration of the island shape. These findings have tentatively been rationalized within a simple model to identify the underlying rate limiting atomistic processes.