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 φ0 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.
@article{arxiv.2305.01003,
title = {Reconstruction-Induced $\varphi_0$ Josephson Effect in Quantum Spin Hall Constrictions},
author = {Lucia Vigliotti and Fabio Cavaliere and Giacomo Passetti and Maura Sassetti and Niccolò Traverso Ziani},
journal= {arXiv preprint arXiv:2305.01003},
year = {2023}
}