Metallic behavior of T-graphene nanotubes

Two various edges are considered: zigzag and armchair (zTGNT and aTGNT). Both types of TGNTs show metallic behaviors regardless of their diameter.

Additionally, Dirac points are observed in the band structure of aTGNTs, with their number increasing as the diameter of the nanotubes increases. Furthermore, with increasing the diameter of the tubes, additional sub-bands and van-Hove singularities appear in the band structure and DOS diagrams, respectively. As a result, the PMS curves exhibit a crossover and can be divided into two parts at different temperature ranges, namely high- and low-temperature.