Electronic and transport properties of graphene nanoflakes with the protrusion of different widths

Theoretical investigation on the transport properties of graphene nanoflakes (GNFs) with protrusions has been performed with density-functional calculations by considering the influence of the structural symmetry. It is found that GNFs with different widths of protrusions exhibit distinctly different transport properties, depending on whether they are mirror symmetric with respect to the midplane (σ) between the two edges. For the symmetric models, electrons primarily pass through the edges of the GNFs with a small transmission probability. On the contrary, the electrons prefer to transit along one side of the GNFs with a high probability in the asymmetric models. Therefore, the conductivity of asymmetric models is greater than that of symmetric models.