Acoustic Solitons in Helicoids and Spiral Graphene Nanoribbons

The dynamics of local regions of longitudinal compression in graphene helicoids and spiral carbon nanoribbons has been numerically simulated. It has been shown that a supersonic acoustic soliton can constantly move without radiation of phonons only in helicoids with transverse radius R < 0.62 nm. Dimensionless velocity s of the soliton in this case falls into the interval 1.0-1.4. In larger radius helicoids and all spiral carbon nanoribbons, the motion of a soliton-like excitation is always accompanied by the intense radiation of phonons (the more the size of the spiral structure, the more intense the radiation).