Topological superconductivity in lead nanowires

TL;DR

This paper investigates lead nanowires created by nanoindentation, demonstrating experimental evidence that suggests the presence of topological superconductivity and Majorana states due to their unique electronic and magnetic properties.

Contribution

It provides experimental analysis of lead nanowires showing signatures consistent with topological superconductivity, a novel observation in such low-dimensional systems.

Findings

Critical current dependence on magnetic field observed

Multiple Andreev reflections detected at finite voltages

Evidence compatible with topological superconductivity

Abstract

Superconductors with an odd number of bands crossing the Fermi energy have topologically protected Andreev states at interfaces, including Majorana states in one dimensional geometries. Superconductivity, a low number of 1D channels, large spin orbit coupling, and a sizeable Zeeman energy, are present in lead nanowires produced by nanoindentation of a Pb tip on a Pb substrate, in magnetic fields higher than the Pb bulk critical field. A number of such devices have been analyzed. In some of them, the dependence of the critical current on magnetic field, and the Multiple Andreev Reflections observed at finite voltages, are compatible with the existence of topological superconductivity.