Hamburg 2001 – wissenschaftliches Programm

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O: Oberflächenphysik

O 36: Hauptvortrag

O 36.1: Hauptvortrag

Freitag, 30. März 2001, 10:15–11:00, B

Diffusion in a Surface: The Atomic Slide Puzzle — •J.W.M. Frenken¹, R. van Gastel¹, E. Somfai², and W. van Saarloos² — ¹Kamerlingh Onnes Laboratory, Leiden University, P.O. Box 9504, 2300 RA Leiden, The Netherlands — ²Instituut-Lorentz, Leiden University, P.O. Box 9504, 2300 RA Leiden

Usually, surface mobility is thought to be restricted completely to the steps and kinks on crystal surfaces. These sites form the natural locations for atoms to come and go. Atoms in the close-packed terraces are often considered to be completely static, since they are tightly packed by their neighbors. In this talk, STM measurements will be shown, which show that a close-packed terrace of a metal surface can be far from static, even at temperatures as low as room temperature! We make the motion visible of the atoms in a Cu(001) terrace, by embedding a low density of In atoms in the first Cu layer. The peculiar characteristics of the motion of the In show that the diffusion of surface vacancies is responsible for a continual reshuffling of all the (In and Cu) atoms in the first layer.

R. van Gastel, E. Somfai, W. van Saarloos and J.W.M. Frenken, Nature, in press.