Josephson coupling through one-dimensional ballistic channel in semiconductor-superconductor hybrid quantum point contacts

Abstract

We study a superconducting quantum point contact made of a narrow In${}_{0.75}$Ga${}_{0.25}$As channel with Nb proximity electrodes. The narrow channel is formed in a gate-fitted constriction of InGaAs/InAlAs/InP heterostructure hosting a two-dimensional electron gas. When the channel opening is varied with the gate, the Josephson critical current exhibits a discretized variation that arises from the quantization of the transverse momentum in the channel. The quantization of Josephson critical current persists down to the single-channel regime, providing an unambiguous demonstration of a semiconductor--superconductor hybrid Josephson junction involving only a single ballistic channel.

6 pages, 4 figures

References in corpus (2)

• Tunable Supercurrent Through Semiconductor Nanowires
• Quantum supercurrent transistors in carbon nanotubes