Critical-Current Oscillations due to Interference Effects in a Clean-Limit Superconductor-Two-Dimensional-Electron-Gas-Superconductor Junction

Abstract

We have confirmed the effects of interference on the superconducting critical current of a gate-fitted superconductor-normal metal-superconductor junction in the clean limit. As the normal metal, the junction uses a two-dimensional electron gas (2DEG), which is well confined in an InAs-inserted-channel InAlAs/InGaAs heterostructure. The superconducting critical current is measured as a function of the gate voltage and shows oscillations as a function of the 2DEG carrier concentration. This oscillation is explained by the Fabry-Pérot interference of the quasi-particles that undergo two normal reflections between two Andreev reflections.