Observation of quantum vortex core fractionalization and skyrmion formation in a superconductor
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. In this study, we report signatures of quantum vortex core fractionalization on the potassium-terminated surface of a multiband superconductor, KFe 2 As 2 . 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 ℂP 2 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.
Article Details
Journal Info
Science
American Association for the Advancement of Science
Authors (17)
Yu Zheng
Quanxin Hu
Tsung-Dao Lee Institute, School of Physics and Astronomy, and State Key Laboratory of Micro-nano Engineering Science, Shanghai Jiao Tong University, Shanghai, China.
Xin Yu
BGI Research, Qingdao, China.
Haijiao Ji
Tsung-Dao Lee Institute, School of Physics and Astronomy, and State Key Laboratory of Micro-nano Engineering Science, Shanghai Jiao Tong University, Shanghai, China.
Igor Timoshuk
Department of Physics, The Royal Institute of Technology, Stockholm, Sweden.
Julien Garaud
Institut Denis Poisson CNRS/UMR 7013, Université de Tours, Tours, France.
Hanxiang Xu
Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China.
Yongwei Li
Tsung-Dao Lee Institute, School of Physics and Astronomy, and State Key Laboratory of Micro-nano Engineering Science, Shanghai Jiao Tong University, Shanghai, China.
Ye Gao
Tsung-Dao Lee Institute, School of Physics and Astronomy, and State Key Laboratory of Micro-nano Engineering Science, Shanghai Jiao Tong University, Shanghai, China.
Xingye Lu
Center for Advanced Quantum Studies, School of Physics and Astronomy, Beijing Normal University, Beijing, China.
Vadim Grinenko
Tsung-Dao Lee Institute, School of Physics and Astronomy, and State Key Laboratory of Micro-nano Engineering Science, Shanghai Jiao Tong University, Shanghai, China.
Egor Babaev
Department of Physics, The Royal Institute of Technology, Stockholm, Sweden.
Noah F. Q. Yuan
Tsung-Dao Lee Institute, School of Physics and Astronomy, and State Key Laboratory of Micro-nano Engineering Science, Shanghai Jiao Tong University, Shanghai, China.
Rui Wu
Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China.
Baiqing Lv
Tsung-Dao Lee Institute, School of Physics and Astronomy, and State Key Laboratory of Micro-nano Engineering Science, Shanghai Jiao Tong University, Shanghai, China.
Chi-Ming Yim
Tsung-Dao Lee Institute, School of Physics and Astronomy, and State Key Laboratory of Micro-nano Engineering Science, Shanghai Jiao Tong University, Shanghai, China.
Hong Ding
Tsung-Dao Lee Institute, School of Physics and Astronomy, and State Key Laboratory of Micro-nano Engineering Science, Shanghai Jiao Tong University, Shanghai, China.