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

Preprints.org

Abstract

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.

Authors 5

1. Lucia Vigliotti corresponding

   University of Genoa

   Affiliation as printed

   Dipartimento di Fisica , Università degli Studi di Genova , Via Dodecaneso 33 , 16146 Genova , Italy;

2. Fabio Cavaliere corresponding

   Superconducting and other Innovative Materials and Devices Institute · University of Genoa

   Affiliation as printed

   CNR-SPIN , Via Dodecaneso 33 , 16146 Genova , Italy

   Dipartimento di Fisica , Università degli Studi di Genova , Via Dodecaneso 33 , 16146 Genova , Italy;

3. Giacomo Passetti Aachen Institut für Theorie der Statistischen Physik

   RWTH Aachen University

   Affiliation as printed

   Institut für Theorie der Statistischen Physik , RWTH Aachen University and JARA-Fundamentals of Future Information Technology , 52056 Aachen , Germany;

4. Maura Sassetti

   Superconducting and other Innovative Materials and Devices Institute · University of Genoa

   Affiliation as printed

   CNR-SPIN , Via Dodecaneso 33 , 16146 Genova , Italy

   Dipartimento di Fisica , Università degli Studi di Genova , Via Dodecaneso 33 , 16146 Genova , Italy;

5. Niccolò Traverso Ziani

   Superconducting and other Innovative Materials and Devices Institute · University of Genoa

   Affiliation as printed

   CNR-SPIN , Via Dodecaneso 33 , 16146 Genova , Italy

   Dipartimento di Fisica , Università degli Studi di Genova , Via Dodecaneso 33 , 16146 Genova , Italy;