Current-injection in a ballistic multiterminal superconductor/two-dimensional electron gas Josephson junction

Abstract

We study the suppression of the critical current in a multi-terminal superconductor/two-dimensional electron gas/superconductor Josephson junction by means of hot carrier injection. As a superconductor Nb is used, while the two-dimensional electron gas is located in a strained InGaAs/InP heterostructure. Two different modes of injection are employed. First, in the three-terminal injection mode, where the injection current flows from an injector contact to one of the superconducting electrodes, only a partial suppression is obtained. Second, in the four-terminal mode, where the injection current flows between two opposite injector contacts, a complete suppression is achieved. A theoretical model for the critical current suppression in a short junction is presented, which takes the two-dimensional character of the junction into account. Qualitatively, the experimental data agree well with the theoretical predictions. The injection voltage required in the experiment to suppress the supercurrent is lower than theoretically predicted. This is explained by the fact that the width of the normal region of the junction is slightly too large to be in the short-junction limit. © 2003 The American Physical Society.