Supercurrent Diode Effect in Helical Superconductors

TL;DR

This paper investigates the supercurrent diode effect in helical superconductors, deriving a general efficiency formula using Ginzburg-Landau theory, and validating it through microscopic calculations and comparisons with previous models.

Contribution

It introduces a comprehensive Ginzburg-Landau framework for the supercurrent diode effect in helical superconductors, including higher gradient terms and microscopic validation.

Findings

Derived a general formula for diode efficiency.

Validated results with microscopic diagrammatic calculations.

Compared with prior quasiclassical approaches.

Abstract

In this work, we explore the generalities of the supercurrent diode effect. As an illustrative example, we examine a model of a two-dimensional superconductor with Rashba-type spin-orbit coupling under an in-plane magnetic field and in the clean limit, which realizes a helical phase. First, we utilize Ginzburg-Landau phenomenology to derive a general formula for the diode efficiency. This is achieved by incorporating higher gradient terms in the Lifshitz invariants, which are responsible for the nonreciprocal superflow. Subsequently, we validate these results through microscopic diagrammatic computation and further estimate correction terms arising from interband pairing correlations. We provide a detailed comparison to prior investigations of this problem conducted within the framework of the quasiclassical approximation based on the Eilenberger equation.