Effects of Commensurability on the Friction and Energy Dissipation in Graphene/Graphene Interface

The commensurability-dependent friction behavior of graphene is investigated using molecular dynamics simulations. The friction force and the dominate frequency of the friction system are calculated when the top graphene slides relative to the bottom graphene with different rotational angles. In commensurate contact, the friction and the energy dissipation are quite large, and the friction force increases with increasing sliding velocity at both zero and room temperature. However, the instantaneous friction is found to present unique behavior in incommensurate contact, such as the sharp reduce of the amplitude of both the friction force and the dominate frequency located around natural frequency of the tip. The interfacial potential barriers and the shearing stiffness under the same normal load with the molecular dynamics simulations is extracted with different rotational angles. It is observed that the topography of the interlayer potential energy and the interfacial stiffness have seen an evident change with commensurate-incommensurate transition. A novel mechanism is proposed which explains the difference of the graphene friction properties under different contact modes. These findings could benefit the modulation of the friction and energy dissipation, and also should be crucial to the application of the graphene-based nanodevices.