近日，上海交通大学丁洪团队报道了超导体中量子涡旋核分馏和斯基子形成的观察。2026年5月21日，《科学》杂志发表了这一成果。

磁场可以以量子涡旋的形式穿透超导体，这些涡旋由一个带有环绕电流的核心奇点构成。伦敦量子化意味着，在单组分超导体中，每个磁通量子对应一个核心奇点。

研究组报道了在多带超导体 KFe₂As₂的钾终止表面上观测到的量子涡旋核心分数化特征。观测发现，单个整数通量涡旋分裂为多个分数涡旋，导致通量量子数与涡旋核心数量之间出现不一致。这些分数涡旋常常排列成链状，理论计算表明，这些链具有 ?P²斯格明子拓扑不变量，从而构成了一种不同类型的拓扑缺陷：手性斯格明子。整数涡旋与分数涡旋（两者共同构成斯格明子）的不同性质，导致了明显不同的光谱特征。

附：英文原文

Title: Observation of quantum vortex core fractionalization and skyrmion formation in a superconductor

Author: Yu Zheng, Quanxin Hu, Xin Yu, Haijiao Ji, Igor Timoshuk, Julien Garaud, Hanxiang Xu, Yongwei Li, Ye Gao, Xingye Lu, Vadim Grinenko, Egor Babaev, Noah F. Q. Yuan, Rui Wu, Baiqing Lv, Chi-Ming Yim, Hong Ding

Issue&Volume: 2026-05-21

Abstract: Magnetic fields can penetrate a superconductor in the form of quantum vortices, which consist of a core singularity with circulating currents. London’s quantization implies that there is one core singularity per quantum of magnetic flux in single-component superconductors. Here, we report signatures of quantum vortex core fractionalization on the potassium-terminated surface of a multiband superconductor KFe2As2. The observed splitting of single integer-flux vortices into several fractional vortices results in a disparity between the numbers of flux quanta and vortex cores. These fractional vortices often arrange in chains, which calculations show are characterized by a P2 skyrmionic topological invariant; this constitutes a different type of topological defect: the chiral skyrmion. The disparate natures of integer and fractional vortices comprising skyrmions lead to distinct spectroscopic signatures.

DOI: ads0189

Source: https://www.science.org/doi/10.1126/science.ads0189