Band-Gap Behaviors of Graphyne-/Graphdiyne-Derived Chiral Nanotubes

In recent years, the graphyne family (GyF), an emerging carbon allotrope, has received increasing attention because of its unique structural and electronic properties. As one member of the GyF, graphyne nanotubes (GyNTs) are considered promising material candidates for various applications. However, the development of GyNTs is still in its early stages, with most studies focusing on zigzag or armchair nanotubes. In this work, a series of GyF-based nanotubes, including graphdiyne nanotubes (GDyNTs) such as γ-GDyNTs and β-GDyNTs, along with δ-GyNTs, β4-GyNTs, T4,4,4-GyNTs, 4,12,2-GyNTs, 4,12,4-GyNTs, and cp-GyNTs, were constructed with (n, 0), (n, n), and chiral (n, m) edges. Density functional tight binding calculations revealed that all γ-GDyNTs, β-GDyNTs, and δ-GyNTs acted as semiconductors with variable dependence on chirality. In contrast, all β4-GyNTs, T4,4,4-GyNTs, 4,12,2-GyNTs, 4,12,4-GyNTs, and cp-GyNTs acted as semimetals with minimal band gaps. This study provides a new approach for producing Gy-/GDy-based conductive devices.