Supercurrent-phase relationship of a Nb/InAs(2DES)/Nb Josephson junction in overlapping geometry

TL;DR

This study experimentally measures the supercurrent-phase relationship of a Nb/InAs(2DES)/Nb Josephson junction, revealing significant deviations from sinusoidal behavior at low temperatures, supported by a theoretical model.

Contribution

It provides the first detailed experimental CPR measurements of a ballistic Nb/InAs(2DES)/Nb junction with a theoretical explanation for observed deviations.

Findings

CPR deviates from sinusoidal at low temperatures

Good agreement between experimental data and theoretical model

Transport measurements support CPR observations

Abstract

Superconductor/normal conductor/superconductor (SNS) Josephson junctions with highly transparent interfaces are predicted to show significant deviations from sinusoidal supercurrent-phase relationships (CPR) at low temperatures. We investigate experimentally the CPR of a ballistic Nb/InAs(2DES)/Nb junction in the temperature range from 1.3 K to 9 K using a modified Rifkin-Deaver method. The CPR is obtained from the inductance of the phase-biased junction. Transport measurements complement the investigation. At low temperatures, substantial deviations of the CPR from conventional tunnel-junction behavior have been observed. A theoretical model yielding good agreement to the data is presented.