Intrinsic supercurrent non-reciprocity coupled to the crystal structure of a van der Waals Josephson barrier.

Kim, Jae-Keun; Jeon, Kun-Rok; Sivakumar, Pranava K; Jeon, Jaechun; Koerner, Chris; Woltersdorf, Georg; Parkin, Stuart S P · Nat Commun · 2024

basic_science · Level V

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Abstract

Non-reciprocal electronic transport in a spatially homogeneous system arises from the simultaneous breaking of inversion and time-reversal symmetries. Superconducting and Josephson diodes, a key ingredient for future non-dissipative quantum devices, have recently been realized. Only a few examples of a vertical superconducting diode effect have been reported and its mechanism, especially whether intrinsic or extrinsic, remains elusive. Here we demonstrate a substantial supercurrent non-reciprocity in a van der Waals vertical Josephson junction formed with a T<sub>d</sub>-WTe<sub>2</sub> barrier and NbSe<sub>2</sub> electrodes that clearly reflects the intrinsic crystal structure of T<sub>d</sub>-WTe<sub>2</sub>. The Josephson diode efficiency increases with the T<sub>d</sub>-WTe<sub>2</sub> thickness up to critical thickness, and all junctions, irrespective of the barrier thickness, reveal magneto-chiral characteristics with respect to a mirror plane of T<sub>d</sub>-WTe<sub>2</sub>. Our results, together with the twist-angle-tuned magneto-chirality of a T<sub>d</sub>-WTe<sub>2</sub> double-barrier junction, show that two-dimensional materials promise vertical Josephson diodes with high efficiency and tunability.