Gate-Defined Topological Josephson Junctions in Bernal Bilayer Graphene
Recent experiments on Bernal bilayer graphene (BLG) deposited on monolayer WSe₂ revealed robust, ultraclean superconductivity coexisting with sizable induced spin-orbit coupling. Here, we propose BLG/WSe₂ as a platform to engineer gate-defined planar topological Josephson junctions, where the normal and superconducting regions descend from a common material. More precisely, we show that if superconductivity in BLG/WSe₂ is gapped and emerges from a parent state with intervalley coherence, then Majorana zero-energy modes can form in the barrier region upon applying weak in-plane magnetic fields. Our results spotlight a potential pathway for "internally engineered" topological superconductivity that minimizes detrimental disorder and orbital-magnetic-field effects.
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© 2023 American Physical Society.
We are grateful to Andrey Antipov, Cory Dean, Cyprian Lewandowski, Alex Thomson, and Yiran Zhang for enlightening discussions. Y.-M. X. acknowledges the support of Hong Kong Research Grant Council through PDFS2223-6S01. É. L.-H. was supported by the Gordon and Betty Moore Foundation's EPiQS Initiative, Grant No. GBMF8682. J. A. was supported by the Army Research Office under Grant No. W911NF-17-1-0323; the Caltech Institute for Quantum Information and Matter, an NSF Physics Frontiers Center with support of the Gordon and Betty Moore Foundation through Grant No. GBMF1250; and the Walter Burke Institute for Theoretical Physics at Caltech. The U.S. Department of Energy, Office of Science, National Quantum Information Science Research Centers, Quantum Science Center supported the symmetry-based analysis of this work. S. N.-P. acknowledges support of Office of Naval Research (Grant No. N142112635) and NSF-CAREER (DMR-1753306) programs. Work at UCSB was supported by the U.S. Department of Energy (Grant No. DE-SC0020305).