Metallic behavior of T-graphene nanotubes

The band structure, density of states (DOS), and Pauli magnetic susceptibility (PMS) of T-graphene nanotubes (TGNT) with different chiralities and diameters are investigated using the tight-binding Hamiltonian model and the Green’s function formalism. 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. The metallic properties of both types of TGNTs are also demonstrated in the PMS curves, which is due to the proportionality of PMS with the DOS. Moreover, the convergence of the DOS curves towards the monolayer is clearly evident as the diameter of both types of TGNT increases to significant values.

Methods
Computational codes have been provided in the Fortran 90, and we have computed the eigenvalues of matrices and the band structures numerically using the LAPACK library. The data file contains two folders of zig zag and armchair T-graphene nanotube data. In each folder, there are three data files of band structure, DOS, and PMS for each diameter.