Determination of the current-phase relation of an InAs 2DEG Josephson junction with a microwave resonator

TL;DR

This study characterizes an InAs 2DEG Josephson junction using a microwave resonator to measure its current-phase relation and interference effects, providing detailed insights into its magnetic field responses for quantum device applications.

Contribution

It introduces a method to determine the current-phase relation of an InAs 2DEG Josephson junction using a microwave resonator, revealing magnetic field-induced interference asymmetries.

Findings

Gate-dependent current-phase relation measured

Supercurrent interference observed in out-of-plane magnetic fields

Interference pattern becomes asymmetric under in-plane magnetic fields

Abstract

Semiconductor-superconductor hybrid nanocircuits are of high interest due to their potential applications in quantum computing. Semiconductors with a strong spin-orbit coupling and large $g$-factor are particularly attractive since they are the basic building blocks of novel qubit architectures. However, for the engineering of these complex circuits, the building blocks must be characterized in detail. We have investigated a Josephson junction where the weak link is a two-dimensional electron gas (2DEG) hosted in an InAs/InGaAs heterostructure grown on a GaAs substrate. We employed the in-situ epitaxially grown Al layer as superconducting contacts to form an rf SQUID, and also to create a microwave resonator for sensing the Josephson inductance. We determined the gate-dependent current-phase relation, and observed supercurrent interference in out-of-plane magnetic fields. With the application of an in-plane magnetic field, we induced asymmetry in the interference pattern, which was found to be anisotropic in the device plane.