In superconducting quantum interference devices (SQUIDs), the superconducting diode effect may be generated by interference of multiple harmonic components in the current-phase relationships (CPRs) of different branches forming SQUID loops. Through the inclusion of two gate-tunable Josephson junctions in series in each interference branch of a double-loop SQUID, we demonstrate independent control over both the harmonic content and the amplitude of three interfering CPRs, facilitating significant improvement in the maximum diode efficiency. Through optimized gate-controlled tuning of individual Josephson energies, diode efficiency exceeding 50% is demonstrated. Flux-dependent oscillations show quantitative agreement with a simple model of SQUID operation.
@article{arxiv.2512.14909,
title = {High efficiency superconducting diode effect in a gate-tunable double-loop SQUID},
author = {Wyatt Gibbons and Teng Zhang and Kevin Barrow and Tyler Lindemann and Jukka I. Väyrynen and Michael J. Manfra},
journal= {arXiv preprint arXiv:2512.14909},
year = {2026}
}