2025-12-29 バッファロー大学（UB）
This illustration shows how superconductivity from vanadium (yellow) is transformed at the magnesium oxide barrier (green), enabling iron (blue) to form same-spin electron pairs and participate in Josephson-junction-like behavior. Photo: Igor Žutić/University at Buffalo
＜関連情報＞
- https://www.buffalo.edu/news/releases/2025/12/josephson-junctions-are-possible-with-only-one-superconductor.html
- https://www.nature.com/articles/s41467-025-64493-w
軌道対称性制御スピン軌道相互作用を持つ超伝導体/強磁性体接合における巨大ショットノイズ Giant shot noise in superconductor/ferromagnet junctions with orbital-symmetry- controlled spin-orbit coupling
César González-Ruano,Chenghao Shen,Pablo Tuero,Coriolan Tiusan,Yuan Lu,Jong E. Han,Igor Žutić & Farkhad G. Aliev
Nature Communications Published:28 October 2025
DOI:https://doi.org/10.1038/s41467-025-64493-w
Abstract
By measuring the shot noise, a consequence of charge quantization, in super-conductor/insulator/ferromagnet (V/MgO/Fe) junctions, we discover a giant increase, orders of magnitude larger than expected. The origin of this giant noise is a peculiar realization of a superconducting proximity effect, where a simple superconductor influences its neighbors. Our measurements reveal largely unexplored implications of orbital-symmetry-controlled proximity effects. The importance of orbital symmetries and the accompanying spin-orbit coupling is manifested by an unexpected emergence of another superconducting region, strikingly different from the parent superconductor. Unlike vanadium’s common spin-singlet superconductivity, the broken inversion symmetry in V/MgO/Fe junctions and the resulting interfacial spin-orbit coupling lead to the formation of spin-triplet superconductivity across the ferromagnetic iron. Here, we show that the enhanced shot noise, known from Josephson junctions with two superconductors, is measured even in a single superconductor. This discovery motivates revisiting how the spin-orbit coupling and superconducting proximity effects can transform many materials.
