Quantum 2025 – wissenschaftliches Programm
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MON: Monday Contributed Sessions
MON 11: Quantum Transport I
MON 11.6: Vortrag
Montag, 8. September 2025, 15:30–15:45, ZHG104
Unconventional Josephson Supercurrent Diode Effect Induced by Chiral Spin-Orbit Coupling — •Andreas Costa1, Osamu Kanehira2, Hiroaki Matsueda2, and Jaroslav Fabian1 — 1University of Regensburg, Germany — 2Tohoku University, Japan
First-principles calculations have recently predicted that chiral materials lacking mirror symmetries---such as twisted van der Waals homobilayers---can feature unconventional radial Rashba coupling with spins aligned fully parallel (instead of tangential) to momentum.
In this talk, we will address Josephson transport through vertical superconductor/ferromagnet/superconductor junctions hosting crossed (radial and tangential) Rashba fields at the interfaces and demonstrate that their interplay with ferromagnetic exchange can lead to supercurrent rectification even when the magnetization is collinear with the current. This so-called unconventional supercurrent diode effect (SDE) originates from spin precessions inside the ferromagnet, which imprint polarity-dependent transmission probabilities on the Cooper pairs being well-distinct from the conventional SDE, and provides a sensitive probe of chiral spin textures.
This work, published in Phys. Rev. B 111, L140506 (2025), has been supported by DFG Grants 454646522 and 314695032 (SFB 1277).
Keywords: Superconductivity; Josephson junctions; supercurrent diode effect; spin-orbit coupling; chirality