Reconstruction-Induced \(\varphi_0\) Josephson Effect in Quantum Spin Hall Constrictions

The simultaneous breaking of time-reversal and inversion symmetry, in connection to superconductivity, leads to transport properties with disrupting scientific and technological potential. Indeed, the anomalous Josephson effect and the superconducting-diode effect hold promises to enlarge the techno...

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Bibliographic Details
Published in:arXiv.org 2023-05
Main Authors: Vigliotti, Lucia, Cavaliere, Fabio, Passetti, Giacomo, Sassetti, Maura, Niccolò Traverso Ziani
Format: Article
Language:English
Subjects:
Channels
Josephson effect
Josephson junctions
Superconductivity
Superconductors
Symmetry
Temperature dependence
Topological insulators
Transport properties
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Summary:The simultaneous breaking of time-reversal and inversion symmetry, in connection to superconductivity, leads to transport properties with disrupting scientific and technological potential. Indeed, the anomalous Josephson effect and the superconducting-diode effect hold promises to enlarge the technological applications of superconductors and nanostructures in general. In this context, the system we theoretically analyze is a Josephson junction (JJ) with coupled reconstructed topological channels as a link; such channels are at the edges of a two-dimensional topological insulator (2DTI). We find a robust \(\varphi_0\) Josephson effect without requiring the presence of external magnetic fields. Our results, which rely on a fully analytical analysis, are substantiated by means of symmetry arguments: Our system breaks both time-reversal symmetry and inversion symmetry. Moreover, the anomalous current increases as a function of temperature. We interpret this surprising temperature dependence by means of simple qualitative arguments based on Fermi's golden rule.
ISSN:2331-8422
DOI:10.48550/arxiv.2305.01003