Fluxoid-induced pairing suppression and near-zero modes in quantum dots coupled to full-shell nanowires

We analyze the subgap excitations and phase diagram of a quantum dot (QD) coupled to a semiconducting nanowire fully wrapped by a superconducting (S) shell. We take into account how a Little-Parks (LP) pairing fluxoid (a winding in the S phase around the shell) influences the proximity effect on the...

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Bibliographic Details
Authors: Escribano, Samuel D., Levy Yeyati, Alfredo, Aguado, Ramón, Prada, Elsa, San-José, Pablo
Format: article
Status:Published version
Publication Date:2022
Country:España
Institution:Consejo Superior de Investigaciones Científicas (CSIC)
Repository:DIGITAL.CSIC. Repositorio Institucional del CSIC
OAI Identifier:oai:digital.csic.es:10261/375874
Online Access:http://hdl.handle.net/10261/375874
https://www.scopus.com/inward/record.uri?eid=2-s2.0-85124170825&doi=10.1103%2fPhysRevB.105.045418&partnerID=40&md5=ac6b566cfffe0f2d70ea6f949c192c2e
Access Level:Open access
Description
Summary:We analyze the subgap excitations and phase diagram of a quantum dot (QD) coupled to a semiconducting nanowire fully wrapped by a superconducting (S) shell. We take into account how a Little-Parks (LP) pairing fluxoid (a winding in the S phase around the shell) influences the proximity effect on the dot. We find that under axially symmetric QD-S coupling, shell fluxoids cause the induced pairing to vanish, producing instead a level renormalization that pushes subgap levels closer to zero energy and flattens fermionic parity crossings as the coupling strength increases. This fluxoid-induced stabilization mechanism has analoges in symmetric S-QD-S Josephson junctions at phase π, and can naturally lead to patterns of near-zero modes weakly dispersing with parameters in all but the zeroth lobe of the LP spectrum. © 2022 American Physical Society.