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Updated: Jul 8, 2026

In Situ SIMS and IR Spectroscopy of Well-defined Surfaces Prepared by Soft Landing of Mass-selected Ions
Published on: June 16, 2014
Alloying at surfaces by the migration of reactive two-dimensional islands
A K Schmid1, N C Bartelt, R Q Hwang
1Sandia National Laboratories, Livermore, CA 94551, USA.
Abstract:
We have studied the formation kinetics of the copper-tin alloy bronze when tin is deposited on the (111) surface of copper at room temperature. Low-energy electron microscopy and atomic-resolution scanning tunneling microscopy reveal that bronze forms on the surface by a complicated, unanticipated cooperative mechanism: Ordered two-dimensional tin islands containing several hundred thousand atoms spontaneously sweep across the surface, leaving bronze alloys in their tracks. We propose that this process, driven by surface free energy, is a version of the "camphor dance" observed on liquid surfaces, and should be a general mechanism of surface alloying when surface diffusion is faster than exchange into the substrate.
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