Fig. 2: Scaling of Josephson supercurrent non-reciprocity with magnetic field strength.
a–c Positive and negative Josephson critical current \({I}_{c}^{+}\) (green) and \(\left|{I}_{c}^{-}\right|\) (orange) versus in-plane (IP) magnetic field \({\mu }_{0}{H}_{\parallel }\) for a 2 nm, b 7 nm, and c 60 nm thick Td-WTe2 barriers in a NbSe2/Td-WTe2/NbSe2 Josephson junction. The measurement was conducted at T = 200 mK for the 2 nm and 7 nm thick junctions and T = 20 mK for the 60 nm thick junction, respectively. Note that the I–V curves of 7 nm thick barrier JJs reveal no significant difference between 200 and 20 mK (Supplementary Information S7), as would be expected for the measurement temperature of ≤ 0.3 T/Tc (Fig. 4b). d–f Josephson diode efficiency (\(\eta=\frac{{I}_{c}^{+}-\left|{I}_{c}^{-}\right|}{{I}_{c}^{+}+\left|{I}_{c}^{-}\right|}\)) as a function of \({\mu }_{0}{H}_{\parallel }\) for d 2 nm, e 7 nm, and f 60 nm thick Td-WTe2 barriers. Note that the pink fits indicate a linear scaling behavior of the diode efficiency with \({\mu }_{0}{H}_{\parallel }\) up to a critical field, above which the diode efficiency drops.
