Dynamics of surface graphene ripplocations on a flat graphite substrate

Surface and bulk ripplocations in layered nanomaterials have recently attracted the attention of researchers because they possess the properties of topological solitons, which are capable of efficient transportof mass and energy and of mediating plastic deformation. In a ripplocation, one or a few layers at the surface or in the bulk of a material are bent or folded. So far, only the static properties of ripplocations have been analyzed. In the present study, the dynamics of graphene bubbles and folds on a graphite substrate are analyzed by full-atomic molecular dynamics and with the help of the two-dimensional chain model. It is demonstrated that such objects, classified as surface ripplocations, are robust solitary waves that propagate while practically radiating no energy. Energy and geometrical parameters of the ripplocations are calculated as the functions of their propagation velocity. In the presence of thermal fluctuations the ripplocations can be accelerated or decelerated, showing a random-walk-like dynamics. Collisions of ripplocations result in their merger. Overall, our results reveal that layered materials can support surface ripplocations that are highly mobile topological solitary waves efficiently transporting mass and energy.