Electronic transport between quantum Hall states and quantum anomalous Hall states in a graphene nanoribbon based heterojunction.

We theoretically investigate the electronic transport between quantum Hall states and quantum anomalous Hall states in a zigzag edged graphene nanoribbon based two-terminal heterojunction. The electrical conductance of the system is calculated by the method of the non-equilibrium Green's function and Landauer-Büttiker formula. We find perfect transmission through the junction when the propagation direction of the charge carriers is the same at the same edge in both regions. However, when the propagation direction at the same edge is the opposite, the electrical conductance is smaller than the quantized value. In this case, snake states at the interface are responsible for the transmission. The results are explained with the aid of the local density of states near the interface. For higher magnetic field in the quantum Hall region or larger ribbon width, the edge states are better realized and quantized electrical conductance is strengthened. Finally, the effects of Anderson disorder and dephasing on the transmission are discussed.