Mechanical Engineering Faculty Research
Thermal Activation in Atomic Friction: Revisiting the Theoretical Analysis
The effect of thermal activation on atomic-scale friction is often described in the framework of the Prandtl–Tomlinson model. Accurate use of this model relies on parameters that describe the shape of the corrugation potential β and the transition attempt frequency f0. We show that the commonly used form of β for a sinusoidal corrugation potential can lead to underestimation of friction, and that the attempt frequency is not, as is usually assumed, a constant value, but rather varies as the energy landscape evolves. We partially resolve these issues by demonstrating that numerical results can be captured by a model with a fitted β and using harmonic transition state theory to develop a variable form of the attempt frequency. We incorporate these developments into a more accurate and generally applicable expression relating friction to temperature and velocity. Finally, by using a master equation approach, we verify the improved analytical model is accurate in its expected regime of validity.
Journal of Physics:Condensed Matter
Dong, Yalin; Perez, D.; Gao, H.; and Martini, A., "Thermal Activation in Atomic Friction: Revisiting the Theoretical Analysis" (2012). Mechanical Engineering Faculty Research. 288.