Deformation of single-walled carbon nanotubes by interaction with graphene: a first-principles study.

The interaction between single-walled carbon nanotubes (SWNTs) and graphene were studied with first-principles calculations. Both SWNTs and single-layer graphene (SLG) or double-layer graphene (DLG) display more remarkable deformations with the increase of SWNT diameter, which implies a stronger interaction between SWNTs and graphene. Besides, in DLG, deformation of the upper-layer graphene is less than in SLG. Zigzag SWNTs show stronger interactions with SLG than armchair SWNTs, whereas the order is reversed for DLG, which can be interpreted by the mechanical properties of SWNTs and graphene. Density of states and band structures were also studied, and it was found that the interaction between a SWNT and graphene is not strong enough to bring about obvious influence on the electronic structures of SWNTs.