Suppression of Josephson currents in ballistic junctions by an injection current

Control of the critical current in a superconductor/two-dimensional electron gas Josephson junction by means of an injection current is reported. The control mechanism is explained by a theoretical model, which takes ballistic transport across the junction and diffusive transport through the semiconductor wire structure into account. Measurements on a Nb-AlGaSb/InAs-Nb junction show that the strong suppression of the critical current can, in principle, be explained by the theoretical model. Deviations are due to the nonlinear current–voltage characteristics of the superconductor/two-dimensional electron gas interface and the two-dimensionality of the supercurrent transport.