Long-range supercurrents through a chiral non-collinear antiferromagnet in lateral Josephson junctions

• Published in: Nature materials Vol. 20; no. 10; pp. 1358 - 1363
• Main Authors: Jeon, Kun-Rok, Hazra, Binoy Krishna, Cho, Kyungjune, Chakraborty, Anirban, Jeon, Jae-Chun, Han, Hyeon, Meyerheim, Holger L., Kontos, Takis, Parkin, Stuart S. P.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.10.2021; Nature Publishing Group
• Subjects: 142/126; 639/301/119/1003; 639/766/119/1001; Antiferromagnetism; Biomaterials; Chemistry and Materials Science; Condensed Matter Physics; Cooper pairs; Electrodes; Josephson junctions; Letter; Magnetic fields; Materials Science; Nanotechnology; Optical and Electronic Materials; Physics; Quantum mechanics; Thin films; Superconducting properties and materials; Spintronics
• ISSN: 1476-1122; 1476-4660
• DOI: 10.1038/s41563-021-01061-9

The proximity-coupling of a chiral non-collinear antiferromagnet (AFM) 1 – 5 with a singlet superconductor allows spin-unpolarized singlet Cooper pairs to be converted into spin-polarized triplet pairs 6 – 8 , thereby enabling non-dissipative, long-range spin correlations 9 – 14 . The mechanism of this conversion derives from fictitious magnetic fields that are created by a non-zero Berry phase 15 in AFMs with non-collinear atomic-scale spin arrangements 1 – 5 . Here we report long-ranged lateral Josephson supercurrents through an epitaxial thin film of the triangular chiral AFM Mn 3 Ge (refs. 3 – 5 ). The Josephson supercurrents in this chiral AFM decay by approximately one to two orders of magnitude slower than would be expected for singlet pair correlations 9 – 14 and their response to an external magnetic field reflects a clear spatial quantum interference. Given the long-range supercurrents present in both single- and mixed-phase Mn 3 Ge, but absent in a collinear AFM IrMn 16 , our results pave a way for the topological generation of spin-polarized triplet pairs 6 – 8 via Berry phase engineering 15 of the chiral AFMs. Long-range lateral Josephson supercurrents are observed in a chiral non-collinear antiferromagnet, indicating topologically generated triplet pairing states.