Computational Investigation of the Effect of Atomic Thermal Fluctuations on the Stick-Slip Motion in Friction Force Microscopy

Abstract

We investigate the effect of thermal fluctuation of atoms on the stick-slip motion observed in friction force microscopy (FFM) using a computational model that couples atomic motion at the interfacial region with the torsional motion of the FFM cantilever. The proposed model enables studying friction over a wide range, starting from the atomic scale at the interface to the macroscopic scale at the cantilever. We show that the thermal fluctuation of the atoms in the interfacial region at a finite temperature aids in crossing the potential barrier, thus inducing the slip motion of the cantilever. Our results show that thermal fluctuation affects the velocity dependence of the friction force, and this result is qualitatively consistent with the thermally activated Prandtl–Tomlinson model of kinetic friction.