Collaborative Work on Chiral-Antiferromagnetism-Enhanced Josephson Supercurrent Published in Physical Review B
Our collaborative study on the Josephson effect in chiral antiferromagnets, conducted with the group of Prof. Songbo Zhang at Hefei National Laboratory and Prof. Bjoern Trauzettel at the University of Würzburg, has been published in Physical Review B 112, 075305 (2025). The study reveals a mechanism by which chiral antiferromagnetic order enhances the Josephson supercurrent and shows that the enhanced supercurrent is stabilized in a π-junction state.
Magnetic order generally disrupts superconducting pairing and suppresses Josephson supercurrents. This collaborative study demonstrates that chiral antiferromagnets with noncollinear magnetic order and valley-locked spin textures can exhibit fundamentally different superconducting transport. In the strong spin-splitting regime, chiral antiferromagnetic order induces dominant equal-spin triplet pairing together with pronounced momentum-space fluctuations of singlet pairing. Both pairing channels facilitate coherent Cooper-pair transport across the junction and substantially enhance the Josephson supercurrent.
The study further shows that the enhanced supercurrent is accompanied by a robust π-junction state and persists over a broad energy range as well as across different temperatures and junction lengths. The proposed mechanism also provides a possible theoretical explanation for the unexpectedly large Josephson currents recently observed in Mn3Ge junctions, offering new insights into the interplay between unconventional antiferromagnetism and superconductivity.