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Nothing moves a surface: vacancy mediated surface diffusion

R. van Gastel·E. Somfai·S. B. van Albada·W. van Saarloos·J. W. M. Frenken
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Abstract

We report scanning tunneling microscopy observations, which imply that all atoms in a close-packed copper surface move frequently, even at room temperature. Using a low density of embedded indium `tracer' atoms, we visualize the diffusive motion of surface atoms. Surprisingly, the indium atoms seem to make concerted, long jumps. Responsible for this motion is an ultra-low density of surface vacancies, diffusing rapidly within the surface. This interpretation is supported by a detailed analysis of the displacement distribution of the indium atoms, which reveals a shape characteristic for the vacancy mediated diffusion mechanism that we propose.

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R. van Gastel, E. Somfai, S. B. van Albada, W. van Saarloos, J. W. M. Frenken. 2000-09-28. Nothing moves a surface: vacancy mediated surface diffusion. https://doi.org/10.1103/physrevlett.86.1562

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