Molecular Dynamics Study of Graphene Nanoflake Shuttle Device on Graphene Nanoribbon with Carbon Nanotube Blocks.

Superlubric motions of graphene nanoflakes (GNFs) on graphene have opened up more applications of graphene for micromachines and nanomachines. Here, we investigate the dynamic behavior of a GNF shuttle on a graphene nanoribbon (GNR) with carbon nanotube (CNT) blocks via molecular dynamics simulations. The GNF moves on a GNR superlubrically, and the CNTs as building blocks induce bistable potential wells so that the GNF is stabilized. MD simulation results indicate that when a GNF shuttle approaches the CNTs, a potential well is created by an increase in the attractive van der Waals energy between the GNF and CNTs, and bistability at the local energy minima positions can be achieved near the CNTs. In order for the GNF shuttle to escape the local energy minima positions, a high external force must be applied to overcome the potential energy barrier. However, after the GNF shuttle escapes from one of the bistable positions, only a low external force is required to stabilize the GNF shuttle. This work explicitly demonstrates that a GNF-GNR/CNT system could be applied to alternative nonvolatile memory and high-speed mass storage by using GNR-CNT arrays.