A phenomenological theory of superconductor diodes

TL;DR

This paper develops a generalized Ginzburg-Landau theoretical framework to understand superconductor diodes, particularly focusing on systems with Rashba spin-orbit coupling, providing analytical and numerical insights into their nonreciprocal critical currents.

Contribution

It introduces a generalized Ginzburg-Landau model with higher-order terms to describe superconductor diodes, including analytical relations for Rashba systems and numerical analysis for broader parameters.

Findings

Analytical relations between nonreciprocal critical currents and system parameters.

Numerical results supporting the theoretical model.

General design principles for superconductor diodes.

Abstract

We study theoretically the superconductor diodes, where the magnitude of the critical current changes as the direction is reversed, in terms of a generalized Ginzburg-Landau model with the higher-order terms in the momentum of the order parameter. This theory is applied to Rashba spin-orbit coupled systems, where analytical relations between the nonreciprocal critical currents and the system parameters are achieved. Numerical calculations with mean-field theory are also obtained to study broader parameter regions. These results offer a rather general description and design principles of superconductor diodes.