Voltage-tunable field-free Josephson diode

TL;DR

This paper demonstrates a voltage-tunable Josephson diode effect in hybrid nanowire junctions with spin-orbit coupling, ferromagnetic insulators, and superconductors, enabling zero-field operation and control via gate voltage.

Contribution

It introduces a gate-tunable Josephson diode effect in hybrid nanowire devices with zero-field operation, advancing control over nonreciprocal supercurrent transport.

Findings

Diodes exhibit nonreciprocal supercurrent with gate-dependent efficiency.

Hysteretic superconducting window as a function of magnetic field.

Operation persists with remanent magnetization, enabling zero-field functionality.

Abstract

We report a gate-tunable Josephson diode effect in hybrid nanowire junctions consisting of a spin-orbit-coupled semiconductor core coated with epitaxial ferromagnetic insulator and superconductor shells. The wires display a hysteretic superconducting window as a function of axial magnetic field. In the superconducting regime, the devices exhibit nonreciprocal supercurrent transport, with the diode efficiency showing a strong dependence on back-gate voltage. The effect persists in a remanent magnetization state following a controlled demagnetization procedure, establishing zero-field operation. These findings demonstrate a voltage-controlled Josephson diode in a single junction and suggest a route toward probing intrinsically broken inversion and time-reversal symmetries in hybrid materials.