The superconducting version of a diode effect has been the subject of extensive research in the past few years. So far, the focus has almost exclusively been on charge transport, but a natural question is whether it is possible to obtain nonreciprocal spin transport without dissipation. Here, we demonstrate that it is possible to generate electrically tunable nonreciprocal spin transport carried by a supercurrent using superconductor/ferromagnet multilayers. The nonreciprocal spin supercurrent reaches an ideal efficiency of 100%, meaning that the spin-polarization of the critical current is finite in one flow direction whereas it vanishes in the other direction. We explain the underlying physics generating this phenomenon. This result provides a way to integrate nonreciprocal supercurrents with spin-polarization, offering new functionality in quantum technologies based on Josephson junctions.
@article{arxiv.2410.07337,
title = {Voltage-tunable spin supercurrent nonreciprocity reaching 100% efficiency},
author = {Chi Sun and Johanne Bratland Tjernshaugen and Jacob Linder},
journal= {arXiv preprint arXiv:2410.07337},
year = {2025}
}