Abstract
Friction between two objects can be understood by the making, stretching, and breaking of thousands of atomic-scale asperities. We have probed single atoms in a nonisotropic surface [the H-terminated Si(100) surface] with a lateral force microscope operating in noncontact mode. We show that these forces are measurably different, depending upon the direction. Experimentally, these differences are observable in both the line profiles and the maximum stiffnesses. Density functional theory calculations show a concerted motion of the whole Si dimer during the tip-sample interaction. These results demonstrate that on an asperity-by-asperity basis, the surface atomic structure plays a strong role in the directional dependence of friction.
- Received 26 April 2013
DOI:https://doi.org/10.1103/PhysRevLett.111.126103
© 2013 American Physical Society
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Friction at the Atomic Scale
Published 18 September 2013
A new experimental method based on atomic force microscopy allows the investigation of friction at the scale of individual atoms.
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