Gate Tunable Josephson Diode Effect in Josephson Junctions made from InAs Nanosheets

TL;DR

This paper reports the observation of a gate-tunable Josephson diode effect in InAs nanosheet-based Josephson junctions, driven by spin-orbit interaction, with potential applications in superconducting electronics and detecting new superconducting states.

Contribution

It demonstrates the first gate-tunable Josephson diode effect in semiconductor nanosheets, highlighting the role of Rashba spin-orbit interaction in this phenomenon.

Findings

JDE depends on magnetic field angle, maximized when perpendicular to bias current

Diode efficiency can be completely suppressed by gate voltages

JDE likely arises from Rashba spin-orbit interaction in InAs nanosheets

Abstract

We report the observation of Josephson diode effect (JDE) in hybrid devices made from semiconductor InAs nanosheets and superconductor Al contacts. By applying an in-plane magnetic field ($B_{\mathrm{xy}}$), we detect non-reciprocal superconducting switching current as well as non-reciprocal superconducting retrapping current. The strength of the JDE depends on the angle between the in-plane magnetic field and the bias current ($I_{\mathrm{b}}$), reaching its maximum when $B_{\mathrm{xy}} \perp I_{\mathrm{b}}$ and dropping to nearly zero when $B_{\mathrm{xy}}\parallel I_{\mathrm{b}}$. Additionally, the diode efficiency is tunable via an electrostatic gate with a complete suppression at certain gate voltages. Our findings indicate that the observed JDE in InAs nanosheet-based Josephson junctions most likely arises from the Rashba spin-orbit interaction (SOI) in the nanosheets. Such gate-tunable JDE in Josephson junctions made from semiconductor materials with SOI is useful not only for constructing advanced superconducting electronics but also for detecting novel superconducting states.