Structural and Electronic Properties of α2-Graphyne Nanotubes: A Density Functional Theory Study

Another form of carbon-based two-dimensional material in the graphene family, named the alpha 2-graphyne sheet, was predicted very recently. The alpha 2-graphyne sheet was created by doubling each acetylenic linker in an alpha-graphyne sheet. It exhibited semimetallic Dirac point features similar to graphene and alpha-graphyne sheets. In the present work, single - walled carbon nanotubes based on an alpha 2-graphyne sheet was introduced. The structural and electronic properties of these nanotubes were studied using density functional theory. It was found that armchair alpha 2-graphyne nanotubes showed metallic behavior, while zigzag alpha 2-graphyne nanotubes were found to have semiconducting or metallic properties depending on tube size. The energy band gap of zigzag alpha 2-graphyne nanotubes decreased with increasing tube diameter. The results indicated that the alpha 2-graphyne sheet and its nanotubes can be proper materials for future nanoelectronics.