Observation of Maximum Supercurrent Quantization in a Superconducting Quantum Point Contact

Abstract

We have confirmed the quantization of the critical current in a superconducting quantum point contact consisting of a split-gate superconductor-(two-dimensional electron gas)-superconductor junction. The critical current and conductance show stepwise changes as a function of the gate voltage. We also observed resonant structure resulting from quantum interference of quasiparticles at the step edge.