We describe the results of Brownian dynamics (BD) simulations of an AFM tip scanned on locally suspended few-layer graphene. The effects of surface compliance and sample relaxation are directly related to the observed friction force. We demonstrate that the reduction of friction with increasing number of graphene layers previously reported in (Lee et al., Science, 2010) in case of a narrow scanning tip can be a result of decreased sample deformation energy due to increased local contact stiffness under the scanning tip. Simulations with varying scan rates indicated that surface relaxation at a given temperature can affect the frictional characteristics of atomically thin sheets in a manner not explained by classical thermally activated models.
Citation: Physical Review Letters
Pub Type: Journals
nanotribology, friction, elasticity, viscoelasticity, graphene, simulation, brownian dynamics