2026-11-05 東京大学
概念図：ゲート電圧で制御する超伝導と磁性の融合
＜関連情報＞
- https://www.t.u-tokyo.ac.jp/press/pr2026-11-05-001
- https://www.nature.com/articles/s43246-026-01393-6
強磁性半導体ジョセフソン接合における超伝導と強磁性の相互作用 Interplay of superconductivity and ferromagnetism in ferromagnetic-semiconductor-based Josephson junctions
Hirotaka Hara, Lukas Baker, Axel Leblanc, Shingen Miura, Keita Ishihara, Melissa Mikalsen, Patrick J. Strohbeen, Jacob Issokson, Masaaki Tanaka, Javad Shabani & Le Duc Anh
Communications Materials Published:05 November 2026
DOI:https://doi.org/10.1038/s43246-026-01393-6
Abstract
The interplay between superconductivity and ferromagnetism has long been pursued as a route to unconventional Josephson effects, yet suitable material platforms remain limited. Here we report Josephson junctions based on epitaxial Al/InAs/(Ga,Fe)Sb heterostructures grown by low-temperature molecular beam epitaxy, achieving atomically abrupt superconductor/semiconductor/ferromagnetic-semiconductor interfaces. The devices exhibit clear proximity-induced superconductivity, including multiple Andreev reflections and gate-tunable supercurrents, confirming transparent coupling across the hybrid structure. Under perpendicular magnetic fields, the junctions reveal highly unconventional Fraunhofer interference patterns with hysteresis, flux jumps, asymmetric lobe evolution, and clear nonreciprocity, which are consistent with induced ferromagnetism and broken time-reversal symmetry, and may also indicate the presence of edge-channel transport in the Josephson junctions. Our results demonstrate that ferromagnetic semiconductor heterostructures can serve as a highly tunable platform for exploring proximity-induced superconductivity and superconducting diode effects, and for advancing device concepts at the intersection of magnetism and quantum electronics.
