Electronic and transport properties of T-graphene nanoribbon: Symmetry-dependent multiple Dirac points, negative differential resistance and linear current-bias characteristics

Abstract

Based on the tight-binding method and density functional theory, band structures and transport properties of T-graphene nanoribbons are investigated. By constructing and solving the tight-binding Hamiltonian, we derived the analytic expressions of the linear dispersion relation and Fermi velocity of Dirac-like fermions for armchair T-graphene nanoribbons. Multiple Dirac points, which are triggered by the mirror symmetry of armchair T-graphene nanoribbons, are observed. The number and positions of multiple Dirac points can be well explained by our analytic expressions. Tight-binding results are confirmed by the results from density functional calculations. Moreover, armchair T-graphene nanoribbons exhibit negative differential resistance, whereas zigzag T-graphene nanoribbons have linear current-bias voltage characteristics near the Fermi level.