Superconducting vortices carrying a temperature-dependent fraction of the flux quantum

• 成果类型: Article
• 署名作者: Iguchi, Yusuke; Shi, Ruby A. A.; Kihou, Kunihiro; Lee, Chul-Ho; Barkman, Mats; Benfenati, Andrea L. L.; Grinenko, Vadim; Babaev, Egor; Moler, Kathryn A. A.
• 署名单位: Stanford University; Stanford University; United States Department of Energy (DOE); SLAC National Accelerator Laboratory; Stanford University; National Institute of Advanced Industrial Science & Technology (AIST); Royal Institute of Technology; Shanghai Jiao Tong University; Stanford University
• 刊物名称: SCIENCE
• ISSN/ISSBN: 0036-11292
• DOI: 10.1126/science.abp9979
• 发表日期: 2023-06-23
• 页码: 1244-1247
• 关键词: magnetic-flux; integer

摘要

Magnetic field penetrates type-II bulk superconductors by forming quantum vortices that enclose a magnetic flux equal to the magnetic flux quantum. The flux quantum is a universal quantity that depends only on fundamental constants. In this study, we investigated isolated vortices in the hole-overdoped Ba1-xKxFe2As2 (x = 0.77) by using scanning superconducting quantum interference device (SQUID) magnetometry. In many locations, we observed objects that carried only part of a flux quantum, with a magnitude that varied continuously with temperature. We demonstrated mobility and manipulability of these objects and interpreted them as quantum vortices with nonuniversally quantized (fractional) magnetic flux whose magnitude is determined by the temperature-dependent parameters of a multicomponent superconductor.