Topological superconductivity and anti-Shiba states in disordered chains of magnetic adatoms

Alex Westström*, Kim Pöyhönen, Teemu Ojanen

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

3 Citations (Scopus)
103 Downloads (Pure)

Abstract

Regular arrays of magnetic atoms on a superconductor provide a promising platform for topological superconductivity. In this work, we study the effects of disorder in these systems, focusing on vacancies realized by missing magnetic atoms. We develop approaches that allow treatment of ferromagnetic dense chains as well as long-range hopping ferromagnetic and helical Shiba chains at arbitrary subgap energies. Vacancies in magnetic chains play an analogous role to magnetic impurities in a clean s-wave superconductor. A single vacancy in a topological chain gives rise to a low-lying "anti-Shiba" state below the band edge of a regular magnetic chain. Proliferation of the anti-Shiba band formed by a finite density of hybridized vacancy states leads to deterioration of the topological phase, which exhibits unusual fragility in a particular parameter region in dilute chains. We also consider local fluctuation in the Shiba coupling and discuss how vacancy states could contribute to experimental verification of topological superconductivity.

Original languageEnglish
Article number104519
Pages (from-to)1-12
JournalPhysical Review B
Volume94
Issue number10
DOIs
Publication statusPublished - 23 Sep 2016
MoE publication typeA1 Journal article-refereed

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