Kinetic Monte Carlo theory of sliding friction

OCTAVIO JAVIER FURLONG; WILFRED T. TYSOE

Milwaukee

Congreso; 70th Physical Electronics Conference; 2010

University of Wisconsin

One of the conceptually simplest models that addresses the atomic origins of sliding friction was initially proposed by Tomlinson [G.A. Tomlinson, Philos. Mag. 7, 905 (1929)] which assumes a periodically and sinusoidally varying change in potential energy at the sliding interface. This is most often applied to the case of a single asperity contact, such as might be encountered in atomic force microscope (AFM) experiments. This models has been extensively applied to understanding the temperature and velocity dependence of sliding friction, as well as the stick-slip behavior observed in this type of experiment.In this work we focus on the sliding friction as a function of scanning velocity at the nanometer scale. The process was simulated based on a modified one-dimensional Tomlinson model.Monte Carlo theory was exploited to describe the thermally activated hopping of the contact atoms, where both backward and forward jumps were allowed to occur. By comparing with the Monte Carlo results, improvements to current semiempirical solutions [E. Riedo et al., Phys. Rev. Lett. 91, 084502 (2003)] have been made. also, experimental results of sliding friction on a NaCl(100) using a silicon tip as a function of normal load and scanning velocity [E. Gnecco et al. Phys. Rev. Lett. 84, 1172 (2000)] where successfully simulated. Furthermore, this approach can be particularly useful in cases where the periodic sliding potential is not sinusoidal and is used in this work for the analysis of previously published experimental AFM results that measured the velocity- and load-dependence of the lateral force for a tungsten tip sliding against a mica surface [E. Riedo et al., Phys. Rev. Lett. 91, 084502 (2003)].