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.