Tokuda Masashi, Matsumoto Fumiya, Maeda Noriaki, Higashihara Tomo, Nakao Mai, Watanabe Mori, Lee Sanghyun, Nakamura Ryoya, Maeda Masaki, Jiang Nan, Yue Di, Narita Hideki, Aoyama Kazushi, Mizushima Takeshi, Ohe Jun-Ichiro, Ono Teruo, Jin Xiaofeng, Kobayashi Kensuke, Niimi Yasuhiro
Department of Physics, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan.
Center for Spintronics Research Network, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan.
Sci Adv. 2025 Sep 5;11(36):eadw6625. doi: 10.1126/sciadv.adw6625. Epub 2025 Sep 3.
Topological superconductors are one of the intriguing material groups from the viewpoint of not only condensed matter physics but also industrial applications such as quantum computers based on Majorana fermion. For real applications, developments of thin-film topological superconductors are highly desirable. Bi/Ni bilayer is a possible candidate for thin-film chiral superconductors where the time-reversal symmetry is broken. Here we report the phase shift of resistance oscillations by half flux quantum in a ring-shaped device of epitaxial Bi/Ni bilayer induced by a small magnetic field through the ring. The half quantum fluxoid can be decisive evidence for unconventional superconductors where the superconducting order parameter has an internal degree of freedom. The present result provides a functional operating principle for quantum devices where the phase of the supercurrent can be shifted by [Formula: see text] with a small magnetic field, based on the internal degree of freedom had by topological superconductivity.
从凝聚态物理以及诸如基于马约拉纳费米子的量子计算机等工业应用的角度来看，拓扑超导体是一类引人关注的材料。对于实际应用而言，薄膜拓扑超导体的研发非常必要。Bi/Ni双层膜是时间反演对称性被破坏的薄膜手性超导体的一个可能候选材料。在此，我们报告了通过穿过环形外延Bi/Ni双层膜器件的小磁场，在该器件中由半个磁通量子引起的电阻振荡的相移。半量子磁通oid可以作为超导序参量具有内禀自由度的非常规超导体的决定性证据。基于拓扑超导所具有的内禀自由度，本结果为量子器件提供了一种功能工作原理，即通过小磁场可使超电流的相位以[公式：见原文]发生偏移。
