Evidence of topological Shiba bands in artificial spin chains on superconductors

TL;DR

This paper demonstrates the formation of topological Shiba bands in atomically assembled Mn chains on Nb(110), providing experimental evidence for topologically non-trivial p-wave gaps crucial for topological quantum computing.

Contribution

It reports the first momentum-resolved measurement revealing multi-orbital Shiba bands and identifies a topologically non-trivial p-wave gap in these engineered atomic chains.

Findings

Evidence of multi-orbital Shiba bands in Mn chains

Identification of a topologically non-trivial p-wave gap

Advancement in experimental detection of topological phases

Abstract

A major challenge in developing topological superconductors for implementing topological quantum computing is their characterization and control. It has been proposed that a p-wave gapped topological superconductor can be fabricated with single-atom precision by assembling chains of magnetic atoms on s-wave superconductors with spin-orbit coupling. Here, we analyze the Bogoliubov quasiparticle interference in atom-by-atom constructed Mn chains on Nb(110) and for the first time reveal the formation of multi-orbital Shiba bands using momentum resolved measurements. We find evidence that one band features a topologically non-trivial p-wave gap as inferred from its shape and particle-hole asymmetric intensity. Our work is an important step towards a distinct experimental determination of topological phases in multi-orbital systems by bulk electron band structure properties only.