Symmetry-broken Josephson junctions and superconducting diodes in magic-angle twisted bilayer graphene.

ABSTRACT: The coexistence of gate-tunable superconducting, magnetic and topological orders in magic-angle twisted bilayer graphene provides opportunities for the creation of hybrid Josephson junctions. Here we report the fabrication of gate-defined symmetry-broken Josephson junctions in magic-angle twisted bilayer graphene, where the weak link is gate-tuned close to the correlated insulator state with a moiré filling factor of υ = -2. We observe a phase-shifted and asymmetric Fraunhofer pattern with a pronounced magnetic hysteresis. Our theoretical calculations of the junction weak link-with valley polarization and orbital magnetization-explain most of these unconventional features. The effects persist up to the critical temperature of 3.5 K, with magnetic hysteresis observed below 800 mK. We show h

SUBMITTER: Diez-Merida J 

PROVIDER: S-EPMC10133447 | biostudies-literature | 2023 Apr

REPOSITORIES: biostudies-literature