Probing the intermediate state of type-I superconductor SnAs using Muon Spin Spectroscopy

TL;DR

This study uses muon spin spectroscopy to investigate the superconducting properties and intermediate state of the topologically non-trivial superconductor SnAs, revealing its type-I nature and time-reversal invariance.

Contribution

It provides the first microscopic characterization of SnAs's superconducting state, combining $$SR experiments with ab initio calculations to understand its topological and superconducting properties.

Findings

SnAs is a time-reversal invariant superconductor.

SnAs exhibits type-I superconductivity.

The superconducting phase diagram of SnAs was established.

Abstract

Superconductivity with non-trivial band topology provides a novel platform for exploring topological superconductivity and its quantum applications. A detailed microscopic understanding of the superconducting ground state in such materials is crucial. Here, we report the results of a muon spin rotation/relaxation study ($\mu$SR) of the topologically non-trivial superconductor SnAs, which exhibits superconductivity below 3.74(1) \si{K}. Zero-field (ZF) $\mu$SR data reveal that this system is a time-reversal invariant superconductor, and systematic transverse-field (TF) $\mu$SR measurements unveil the type-I nature of the SnAs superconductor. We have established the superconducting phase diagram to understand the intermediate state of type-I superconductors. Moreover, ab \textit{initio} band structure and phonon calculations are performed, which correlate with the experimental characterization.