Field-free superconducting diode effect in two-dimensional Shiba lattices

TL;DR

This paper proposes a theoretical model for a superconducting diode effect that operates without magnetic fields, utilizing a 2D Shiba lattice with a conical spin texture to achieve non-reciprocal supercurrent flow.

Contribution

The study introduces a novel field-free superconducting diode effect based on a 2D Shiba lattice with a conical spin texture, expanding possibilities for scalable superconducting devices.

Findings

Achieves diode efficiency over 40% without magnetic fields.

Demonstrates strong angular dependence of the diode effect.

Shows tunability of the effect via spin texture pitches.

Abstract

The superconducting diode effect (SDE) refers to non-reciprocal transport, where current flows without resistance in one direction but becomes resistive in the opposite direction, but its typical reliance on magnetic field hinders scalability and device integration. In this article, we present a theoretical framework for realizing a field-free SDE based on a two-dimensional (2D) Shiba lattice featuring a conical spin texture. Using the real-space Bogoliubov-de Gennes (BdG) calculations, we illustrate that the conical spin configuration alone is sufficient to break the necessary inversion and time reversal symmetries, enabling nonreciprocal supercurrent flow without any external magnetic field, yielding diode efficiency exceeding 40%. Furthermore, we find that the efficiency of such a diode effect becomes strongly dependent on the direction of current flow, revealing a pronounced angular dependence that can be tuned by varying the pitches of the spin texture along the two spatial lattice directions. Our findings offer a pathway toward scalable, field-free superconducting components for non-dissipative electronics and quantum technologies.