In-situ tunable superconducting diode: towards field-free operation with infinite nonreciprocity

TL;DR

This paper presents a novel in-situ tunable superconducting diode based on niobium Josephson junctions, achieving magnetic-field-free operation, reconfigurability, and near-infinite nonreciprocity for advanced computing applications.

Contribution

It introduces a four-terminal Josephson junction design that enables broad in-situ tunability and reconfigurability without external magnetic fields, a significant advancement over prior superconducting diode technologies.

Findings

Demonstrated diode operation as Gauss neurons via reentrant superconductivity.

Achieved effectively infinite nonreciprocity within experimental resolution.

Enabled threshold-free AC current rectification with reconfigurable polarity.

Abstract

Efficient, scalable, and magnetic-field-free superconducting diodes are essential for future superconducting electronics; yet, despite significant efforts, such practical devices remain unrealized. The main challenge lies in achieving broad-range in-situ tunability, both for optimization and for achieving transistor-like operation. Here, we study diodes based on four-terminal niobium planar Josephson junctions. We show that the multiterminal structure eliminates the need for an external magnetic field and enables essentially unrestricted in-situ tunability, along with reconfigurability of the diode polarity, leading to new functionality. For example, we demonstrate that such diodes can operate as Gauss neurons via reentrant superconductivity. By deliberately tuning the junction parameters, we obtain effectively infinite nonreciprocity (within experimental resolution) leading to threshold-free ac-current rectification. Such technologically simple, reconfigurable, and broadly tunable diodes could be instrumental for future digital and neuromorphic computing.