Superconducting diode effect in quasi-one-dimensional systems

TL;DR

This paper presents a theoretical model explaining the superconducting diode effect in quasi-one-dimensional systems, highlighting how spin-orbit coupling and quantum confinement influence non-reciprocal critical currents.

Contribution

It introduces a minimal microscopic model derived from Rashba spin-orbit coupled superconductors to analyze non-reciprocal critical currents.

Findings

System parameters like spin-orbit coupling affect diode effect strength

Model aligns with Ginzburg-Landau descriptions

Analytical and numerical exploration of non-reciprocity

Abstract

The recent observations of the superconducting diode effect pose the challenge to fully understand the necessary ingredients for non-reciprocal phenomena in superconductors. In this theoretical work, we focus on the non-reciprocity of the critical current in a quasi-one-dimensional superconductor. We define the critical current as the value of the supercurrent at which the quasiparticle excitation gap closes (depairing). Once the critical current is exceeded, the quasiparticles can exchange energy with the superconducting condensate, giving rise to dissipation. Our minimal model can be microscopically derived as a low-energy limit of a Rashba spin-orbit coupled superconductor in a Zeeman field. Within the proposed model, we explore the nature of the non-reciprocal effects of the critical current both analytically and numerically. Our results quantify how system parameters such as spin-orbit coupling and quantum confinement affect the strength of the superconducting diode effect. Our theory provides a complementary description to Ginzburg-Landau theories of the effect.