High-Field Robust and Polarity-Reversible Superconducting Diode Effect in a Superconductor/Ferromagnet Heterostructure.

The superconducting diode effect (SDE), characterized by nonreciprocal critical supercurrents, plays a key role for next-generation dissipationless electronics. Typically, the SDE requires external magnetic fields to break time-reversal symmetry, limiting its practical applications. Superconductor/ferromagnet heterostructures offer an alternative way to enable field-free nonreciprocal transport by using magnetic proximity effects to break time-reversal symmetry. However, the SDE in these cases generally show a fixed sign of the critical current asymmetry, without any polarity reversal. Therefore, a polarity-reversible SDE with a sign-switchable critical current difference remains unexplored. Here, we demonstrate a high-field robust and polarity-reversible SDE in a van der Waals FeSeTe/Fe3GaTe2 heterostructure. We found that, even though the pristine FeSeTe shows no diode response, the heterostructure exhibits a pronounced zero-field SDE arising from proximity-induced time-reversal symmetry breaking. Notably, the diode polarity can be effectively switched by both temperature and magnetic field. Strikingly, the SDE persists under magnetic fields of up to 10 T, exceeding the operational limits of most reported SDE platforms. These results establish such heterostructures as a versatile materials platform for high-field and polarity-reversible superconducting diodes for low-dissipation rectifiers and superconducting logic devices.