Comment: Superconducting transition in Nb nanowires fabricated using focused ion beam

TL;DR

This paper critiques a previous study on Nb nanowires, arguing that their interpretation of superconducting transition data is flawed and proposing an alternative explanation based on a superconductor-normal metal proximity model.

Contribution

It challenges the thermal and quantum phase slip interpretation and introduces a superconductor-normal metal proximity model as a better explanation.

Findings

The original phase slip analysis is inadequate.

Proposed SN proximity model better fits the data.

Highlights the importance of correct theoretical frameworks.

Abstract

In a recent paper Tettamanzi et al (2009 Nanotechnology \bf{20} 465302) describe the fabrication of superconducting Nb nanowires using a focused ion beam. They interpret their conductivity data in the framework of thermal and quantum phase slips below $T_c$. In the following we will argue that their analysis is inappropriate and incomplete, leading to contradictory results. Instead, we propose an interpretation of the data within a SN proximity model.