Low-Speed Atomistic Simulation of Stick–Slip Friction using Parallel Replica Dynamics
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Atomic stick–slip friction has been predicted by molecular dynamics simulation and observed in experiments. However, direct quantitative comparison of the two has thus far not been possible because of the large difference between scanning velocities accessible to simulations and experiments. In general, the slowest sliding speeds in MD simulations are at least five orders of magnitude larger than the upper limit available to experimentalists. To take a step toward bridging this gap, we have applied parallel replica dynamics, an accelerated molecular dynamics method, to the simulation of atomic stick–slip. The method allows molecular simulations to run parallel in time in order to extend their duration, thereby enabling lower scanning velocities. We show here that this method is able to predict atomic stick–slip friction accurately and efficiently at scanning speeds several orders of magnitude slower than standard molecular dynamics simulations. The accuracy and usefulness of this method is illustrated by correct prediction of the logarithmic dependence of friction on velocity.
KeywordsNanotribology Stick–slip Friction mechanisms
We are grateful for the contributions of Drs. Robert Carpick, Yuri Mishin, and Vladimir Ivanov and to the National Science Foundation for its support via award CMMI-0758604. Work at Los Alamos National Laboratory (LANL) was supported by the United States Department of Energy (U.S. DOE) Office of Basic Energy Sciences, Materials Sciences and Engineering Division, and by the LANL Laboratory Directed Research and Development Program. LANL is operated by Los Alamos National Security, LLC, for the National Nuclear Security Administration of the U.S. DOE under Contract No. DE-AC52-06NA25396.