Structural and electronic properties of T graphene nanotubes: a first-principles study

An allotrope of graphene named T graphene was reported to reveal Dirac-like fermions and high Fermi velocity in its buckled phase similar to graphene. However, these Dirac fermions were questioned to be artificial, caused by band folding under the unstable buckling in T graphene. Here, we report first-principles studies on the structural and electronic properties of T graphene nanotubes which are systems rolled up from the two-dimensional planar sheet of T graphene. The ‘artificial’ Dirac fermions in T graphene are turned into reality in the T graphene nanotubes. Two sets of T graphene nanotubes with different diameters were studied. One set of T graphene nanotubes reveals a semi-metallic property and shows an increasing of the number of Dirac points with the diameters. Another set of T graphene nanotubes reveals a metallic property. Our study indicates that rolling up the allotrope of graphene can provide a new avenue for developing new semimetal materials with fascinating properties.