Quantum interference in asymmetric superconducting nanowire loops

TL;DR

This study investigates how asymmetries in superconducting nanowire loops affect quantum interference and persistent currents, providing insights for designing superconducting quantum devices.

Contribution

It offers the first combined experimental and theoretical analysis of flux modulation in asymmetric superconducting nanowire loops, highlighting the impact of asymmetries.

Findings

Quantitative model explains flux modulation in asymmetric loops

Parameters like persistent and critical currents are identified

Asymmetry effects can inform superconducting device design

Abstract

Macroscopic phase coherence in superconductors enables quantum interference and phase manipulation at realistic device length scales. Numerous superconducting electronic devices are based on the modulation of the supercurrent in superconducting loops. While the overall behavior of symmetric superconducting loops have been studied, the effects of asymmetries in such devices remain under-explored and poorly understood. Here we report on an experimental and theoretical study of the flux modulation of the persistent current in a doubly-connected asymmetric aluminum nanowire loop. A model considering the length and electronic cross-section asymmetries in the loop provides a quantitative account of the observations. Comparison with experiments give essential parameters such as persistent and critical currents as well as the amount of asymmetry which can provide feedback into the design of superconducting quantum devices.