Simulated sliding between an oxidized silicon tip and surface over six decades of velocity using accelerated molecular dynamics (MD) reproduces the experimental velocity dependences of the friction. Unlike in the crystalline case, as increasing forces are applied to the amorphous tip, intermediate states arise. These intermediate states serve as critical transition pathways. The emergence of such states leads to the emergence of a plateau in sliding velocity at lower sliding speeds and higher temperatures. A simple theory based on these observations successfully describes both the experimental and simulated data.

• Received 23 August 2011

DOI:https://doi.org/10.1103/PhysRevB.84.165422

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Published by the American Physical Society