Abstract
Using low-energy electron microscopy, we determine that self-diffusion of the Cu(001) surface is slowed by the presence of a c(2×2)-Pd buried surface alloy. We probe surface diffusion using Cu-adatom island-ripening measurements. On alloyed surfaces, the island decay rate decreases monotonically as the Pd concentration is increased up to ∼0.5 monolayer (ML), where the 2×2 buried alloy is Pd saturated. We propose that the Pd slows island ripening by inhibiting the diffusion of surface vacancies across terraces. For dilute alloys (0.2-ML Pd), this conclusion is supported by density-functional theory calculations, which show that surface vacancies migrate more slowly owing to an attraction to isolated buried Pd atoms. The results illustrate a fundamental mechanism by which even a dilute alloy thin-film coating may act to inhibit surface-diffusion-mediated processes, such as electromigration.
Original language | English (US) |
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Article number | 245440 |
Journal | Physical Review B - Condensed Matter and Materials Physics |
Volume | 84 |
Issue number | 24 |
DOIs | |
State | Published - Dec 21 2011 |
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics