Interference effects on the critical current in a clean-limit superconductor–normal-metal–superconductor junction

Interference effects are confirmed on the 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) with a high mobility of 7.38 m²/Vs and a high carrier density of 1.98×{}10¹² cm^-2 at 4.2 K. The superconducting critical current that flows through the 2DEG 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 interference effects predicted by Chrestin et al. The typical period of the oscillation agrees well with the theoretical prediction.