Theoretical characterization and application of mechanical behavior of atoms/ions migrating on graphene surface

Abstract The static and dynamic mechanical behaviors of atoms/ions migrating on graphene surface are investigated via theoretical and numerical calculations, and a design idea of nano-scale device that can be used for atoms/ions screening is proposed on this basis. By using the Fourier expansion of the interaction potential between atoms, the analytical expression of the interaction force between an atom/ion and infinitely large graphene is derived. The dependence of the interaction force on the vertical distance from the atom/ion to graphene surface and the atomic/ionic types are analyzed. Based on the interaction force, a dynamics governing equation for the migration of atoms/ions on graphene surface is established, and the dynamics behaviors of atoms/ions when they migrate on the graphene surface at different initial velocities are studied. Taking lithium-ion as an example, it is found that there are three migration states along the armchair direction of graphene. No matter which migration state, the lithium-ion will eventually be stably adsorbed above the center of a hexagonal carbon ring (the hollow site). By adjusting the initial velocity, the lithium-ion can be steadily adsorbed at the specified sites, so as to control the migration distance of lithium-ion. What’s more, the functional relationship between the critical initial velocity of the lithium-ion and the stable adsorption sites on graphene surface is given, and the influence of the vertical distance from the lithium-ion to graphene surface on the migration process is analyzed. In addition, the dynamics behaviors of the migration of different atoms/ions on graphene surface are studied, and it is found that the migration of alkali metal particles is more free with the increase of atomic number, and the stable site is further away from the initial position, which is in good agreement with the results of molecular dynamics simulation in the literature. Besides, the effects of initial position, damping and migration path on the dynamics behaviors of atoms/ions migrating on graphene surface are also studied. Finally, on the basis of theoretical results, a design idea of graphene-based nano-scale device is proposed, which can be used to screen specified atoms/ions and control their in and out positions.