A comparison study between the Lennard-Jones and DRIP potentials for friction of graphene layers

Graphene is a one-atom thick 2-D material and has huge potential as a solid lubricant for small length scale devices such as nano/micro-electro-mechanical systems. Atomistic simulations such as molecular dynamics is a popular tool to study the frictional behaviors of graphene layers and it is of critical importance to accurately describe the interlayer interactions in order to give a reliable prediction on the friction of graphene. Here, two interatomic potentials, Lennard-Jones (LJ) potential and dihedral-angle-corrected registry-dependent interlayer (DRIP) potential, are examined to model interlayer interactions in friction simulations of multilayer graphene structures. While both potentials have similar attractive interactions, DRIP models the repulsive interaction by considering transverse distance and dihedral angle. In this study, we investigate the friction properties between two pristine graphene layers. The simulation results reveal that friction forces of the DRIP models are about one order of magnitude larger than those of the LJ models. It turns out that the modification of the repulsive term in DRIP introduces additional energy corrugations which increase the friction force.