Kankona Singha Roy

1 Introduction Until the discovery of fullerenes,[1] it was believed that inherent crystal asymmetry was the only driving force to roll layered structures.[2, 3] Later on it was revealed that flat graphene nanoribbons are unstable and, under the right conditions, spontaneously transform into carbon nanotubes to minimize the energy by eliminating the dangling bonds at the nanoribbons' edges.[4] Tenne et al.