We present a general mechanism for large charge and spin Josephson diode effects in strongly spin-polarized superconductor-ferromagnet hybrid structures with a noncoplanar spin texture, formulated in terms of quantum-geometric phases. We present necessary conditions for this effect to occur, and show numerical results for disordered materials, relevant for applications. We calculate Josephson diode efficiencies for both charge- and spin-diodes and show that a spin-diode efficiency of 100% can be reached. Finally, we present a SQUID device that can switch between nearly pure spin-up and spin-down equal-spin supercurrents across the ferromagnet by reversing the flux. These findings establish functionalities that are absent for coplanar spin textures.
@article{arxiv.2501.11751,
title = {Quantum-geometric spin and charge Josephson diode effects},
author = {Niklas L. Schulz and Danilo Nikolić and Matthias Eschrig},
journal= {arXiv preprint arXiv:2501.11751},
year = {2025}
}