The effect of corner form on electron transport of L-shaped graphene nanoribbons

We study transport properties of two L-shaped graphene nanoribbons (LGNRs) with different corner deformation. It is found that the corner geometry of the L-shaped junction has enormous influence on the electron transport around the Fermi energy. As a triangle graphene flake is added to the inside corner of a metallic right-angle LGNR, a gap appears in the conductance, i.e., the properties of the LGNR transform from metallic to semiconducting. However, as a triangle graphene flake is cut from the deformed semiconducting LGNR, resonant peaks via quasi-bound states exist in the original gap of conductance. The LGNR with deformed inside and outside corners is equivalent to a resonant-tunneling transistor. The quasi-bound states inducing the resonant transmission are confined in the L-shaped junction and strongly dependent on the size of the corner. Thus one can tune the transport properties of LGNR by the structural geometry and size.