Supercurrent control in a multi-terminal Nb-InGaAs/InP junction with Nb injector electrodes

We experimentally studied the effect of an injection current on the Josephson current in a superconductor/two-dimensional electron gas/superconductor junction. The two-dimensional electron gas is realized by using an InGaAs/InP heterostructure while Nb is taken for the superconducting electrodes. The suppression of the Josephson supercurrent by injecting hot carriers from an additional Nb electrode is explained by the modification of the carrier distribution function. The differential conductance between the injector electrode and the Josephson junction is found to be enhanced if the junction is in the superconducting state. This effect is explained by an interference of the quasi-particles which are phase-coherently Andreev reflected between the superconducting junction electrodes. The dependence of this enhancement on an external magnetic field and on the injection current is studied in detail