Impact of magnetic field direction on anti-dot-based superconducting diodes

TL;DR

This paper demonstrates how the superconducting diode effect in niobium films can be controlled by patterning asymmetric antidots, revealing distinct mechanisms under different magnetic field orientations and strengths, supported by simulations and models.

Contribution

It introduces a method to engineer superconducting diodes using patterned antidots, identifying separate control mechanisms for in-plane and out-of-plane magnetic fields.

Findings

Edge flux pinning dominates at low fields and in-plane fields.

Bulk flux pinning influences high-field responses.

Diode efficiency correlates with the pinning landscape.

Abstract

The superconducting diode effect (SDE) is a fundamental building block for dissipationless nonreciprocal electronics, yet its microscopic origins in thin films often involve competing mechanisms that remain debated. Here, we demonstrate that the SDE can be engineered in niobium films by patterning macroscopic asymmetric antidots, revealing distinct control mechanisms under in-plane and out-of-plane magnetic fields. We identify two dominant contributions to nonreciprocal transport: edge flux pinning, which governs the low-field and in-plane field regimes via surface-barrier asymmetry, and bulk flux pinning, which drives the high-field response and correlates directly with the geometric asymmetry of the antidots. Supported by time-dependent Ginzburg-Landau simulations and an analytical model, we provide a unified description of these regimes, linking the diode efficiency to the specific pinning landscape. These findings establish a flexible design principle for engineering superconducting diodes with tunable functionality, paving the way for their integration into next-generation quantum and cryogenic circuits.