Transverse superconducting diode without parity and time-reversal violation

TL;DR

This paper demonstrates a novel transverse superconducting diode effect that does not require breaking parity or time-reversal symmetry, enabling tunable nonreciprocal supercurrents through bias current manipulation.

Contribution

It introduces a new mechanism for superconducting diodes using off-axis bias in anisotropic superconductors, avoiding the need for symmetry breaking.

Findings

Diode efficiency is tunable via bias current amplitude.

Unidirectional superconductivity occurs above a critical bias threshold.

Proposes a current-gated orthogonal superconducting transistor (CGOST).

Abstract

The superconducting diode effect (SDE) is characterized by its nonreciprocal nature in critical supercurrents. However, realizing a longitudinal SDE typically requires simultaneous time-reversal ($\mathcal{T}$) and inversion ($\mathcal{P}$) symmetry breaking in the device, raising challenges in applications. In this Letter, we reveal that an off-axis direct-current bias applied to a planar anisotropic superconductor can convert intrinsic anisotropy into transverse nonreciprocity, generating ultra-tunable SDE without breaking either $\mathcal{P}$ or $\mathcal{T}$ symmetry. Using both Ginzburg-Landau theory and self-consistent mean-field calculations, we show that diode efficiency can be continuously tuned via bias current amplitude. Notably, when the injected bias current exceeds a critical threshold, the system is driven into a ``unidirectional superconductivity" regime, where transverse dissipationless currents are permitted in only one direction. Based on this mechanism, we propose the ``current-gated orthogonal superconducting transistor (CGOST)" and demonstrate its utility in tunable supercurrent range controllers and half-wave rectifiers. Our findings open new avenues for nonreciprocal superconducting electronics.