Dynamics of surface migration in the weak corrugation regime

We report a systematic study for metal-on-metal surface migration in the we ak corrugation regime, i.e., with migration barriers falling below approxim ate to 100 meV. The migration characteristics are elucidated by variable-te mperature scanning tunneling microscopy observations in the 50-200 K temper ature range, which are analyzed by means of nucleation theory. The results demonstrate that, upon entering the weak corrugation regime, the dynamics o f the systems are characterized by increasingly reduced effective preexpone ntial factors, while Arrhenius behavior prevails.