Numerical Simulation Of Vertical Transmission Of Bilayer Graphene

Gears are one of the oldest devices known to mankind.Gears are more indispensable components for machines and equipment with transmission systems in the future of nanotechnology.However,designing gears at nanometer scale is still facing great challenges.The structure formed by stacking nanomaterials in a certain order and direction is called van der Waals heterostructures.Due to the weak van der Waals interaction between layers and the strong in-plane bonding within layers,vd W heterostructures have attracted wide attention.In this paper,we proposed a way to utilize long-range interactions between stacking layers to transmit mechanical motion.The specific research content and conclusions are as follows:1.Firstly,we used molecular statics to study the directional motion of bilayer graphene.The simulation results show that the directional sliding of one layer can cause orthogonal movement of another layer,resulting in gear transmission.The vertical transmission significantly depends on the relative crystallographic orientation of the bilayer graphene.In addition,we used molecular dynamics simulations to study the temperature effect of the transmission.The results show that for infinitely large bilayer graphene,the transmission ratios at different temperatures are almost consistent with the results of the statics study.Based on this directional transmission behavior of graphene,we proposed that van der Waals forces can be used to transfer mechanical motion between nanostructures.These results can be used to design gear components based on two-dimensional nanomaterials.2.Furthermore,we extended our research to more practical graphene nanoribbons.We discovered that the law of motion is not only determined by the crystallographic angle,but also the edge shape of the nanoribbon has an important influence on this transmission phenomenon.Moreover,for transmission ratio the temperature effect is more significant on graphene nanoribbons.By using VMD visualization software,we found that as the temperature increases,the surface fluctuations of graphene nanoribbons become more intense.Comparing with the infinitely large graphene,we hypothesize that the surface wave effect is caused by the edge effect,so it is recommended to eliminate this effect by edge passivation modification.3.From the potential energy distribution,we concluded that the motion trajectory can be clearly explained by the energetically favorable path of the potential energy distribution.The trajectories of the two models are consistent with the energetically favorable path of the potential energy distribution diagram.The energetically favorable path means that we use the steepest descent method to find the fastest direction of potential energy gradient descent,and then connect them in turn.If the energetically favorable path is unique,then the speed will not affect the trajectory.We believe that our results will provide new ideas and understanding for nanodevices that utilize van der Waals interactions between nanostructures,and also have great significance for nanomaterial mechanical motion systems with extreme surface-to-volume ratio.