Transmission through a metallic T-shaped graphene nanoribbon

We investigate the electronic transport through the metallic armchair T-shaped graphene nanoribbon. We found that the conductance spectrum exhibits a well-defined insulating band around the Dirac point. Our calculation also indicates that the defect can destroy the edge state localized at the zigzag-edged shoulder of the junction. When the concentration of the vacancies of each edge is about ρ=13, a notable feature is the conductance insulating band can be completely eliminated. And such a conclusion is independent of the size of the shoulder.