Rotational Friction Correlated with Moire Patterns in Strained Bilayer Graphene: Implications for Nanoscale Lubrication

Energy conservation of graphene nanodevices requires frictional dissipation management for their high surface area to volume rates, and rotational motion besides sliding scenarios appear frequently. Here, the rotational friction between graphene layers is investigated by molecular dynamics simulations with a validated graphene-spring model. It shows that the interlayer frictional torque drops an order of magnitude and approaches superlubricity with the emergence of Moire patterns (MPs). Further analysis reveals that the incommensurate interface of MPs tunes the local energy, which cancels each other out with relative rotation, resulting in ultralow interlayer energy barriers. Accordingly, for bilayer systems with biaxially stretched substrates, a significant torque reduction can be achieved when the size of MPs matches that of the graphene flake. This study would provide new insight into the lubrication of rotatable nanomechanical systems.

Automated summary

This study investigates the rotational friction between graphene layers using molecular dynamics simulations, revealing that the emergence of Moire patterns can lead to superlubricity. Further analysis shows that the incommensurate interface of Moire patterns can tune the local energy, resulting in ultralow interlayer energy barriers. Adjusting the size of Moire patterns to match that of graphene flakes can significantly reduce torque in bilayer systems with biaxially stretched substrates.