Shape resonances in the superconducting order parameter of ultrathin nanowires

TL;DR

This paper investigates how shape resonances in ultrathin cylindrical nanowires significantly alter the superconducting energy gap and transition temperature, with effects much larger than in similar thin films.

Contribution

It provides a numerical analysis of shape resonances in superconducting nanowires, revealing larger resonance effects compared to ultrathin films.

Findings

Resonance effects cause large deviations in the energy gap.

Transition temperature is profoundly affected by shape resonances.

Resonance sizes are an order of magnitude larger than in thin films.

Abstract

We study the shape resonance effect associated with the confined transverse superconducting modes of a cylindrical nanowire in the clean limit. Results of numerical investigations of the Bogoliubov-de Gennes equations show significant deviations of the energy gap parameter from its bulk value with a profound effect on the transition temperature. The most striking is that the size of the resonances is found to be by about order of magnitude larger than in ultrathin metallic films with the same width.