A systematic study was made of metal-on-metal surface migration in the regime where the migration barriers were lower than about 0.1eV. The migration characteristics were revealed by variable-temperature scanning tunnelling microscopic observations at 50 to 200K, and were analyzed in terms of nucleation theory. The results demonstrated that, upon entering the weak corrugation regime, the behaviour of the system was marked by increasingly reduced effective pre-exponential factors, while Arrhenius characteristics were maintained.

Dynamics of Surface Migration in the Weak Corrugation Regime. J.V.Barth, H.Brune, B.Fischer, J.Weckesser, K.Kern: Physical Review Letters, 2000, 84[8], 1732-5