Observation of edge supercurrent in topological antiferromagnet MnBi₂Te₄-based Josephson junctions.

Abstract

Hybridizing superconductivity with topology and magnetism attracts growing interest in condensed matter physics. Here, we present our findings on the measurement of supercurrent induced in an intrinsic antiferromagnetic topological insulator MnBi₂Te₄. By constructing a MnBi₂Te₄ proximity Josephson junction, we observed an anomalously large period of the Fraunhofer patterns, indicating a strong Josephson coupling state. As the MnBi₂Te₄ thickness is reduced, a distinct asymmetric edge supercurrent emerges, aligning consistently with the observed oscillatory junction magnetoresistance. Leveraging this large asymmetric edge supercurrent, we have realized a nonvolatile Josephson diode device with programmable polarity, achieved through training with an out-of-plane magnetic field. Theoretical calculations substantiate that these behaviors are attributed to the interference between the highly asymmetric topological edge channel-mediated supercurrent induced in MnBi₂Te₄. Our study establishes this system as a promising avenue for investigating topological superconductivity, chiral Majorana edge modes, and advanced functionality device applications.