Figure 1
From: Supercurrent switch in π topological junctions based upon a narrow quantum spin Hall insulator
Schematic illustration of the proposed Josephson junction with a gate voltage V g applied on the middle normal segment of width d. The QSH insulator strip with two edges (edges 1 and 2) is sketched as the orange bar. The red and black lines illustrate the helical edge states with the vertical arrows representing the spin orientation, and the interedge coupling causes interedge backscattering indicated by the dotted lines. The two green bars denote the two s-wave SCs deposited on edge 1.
