Observation of superconducting vortices carrying a temperature-dependent fraction of the flux quantum

ORAL

Abstract

This work investigates isolated vortices in the hole-overdoped Ba1-xKxFe2As2 (x=0.77) by using scanning superconducting quantum interference device (SQUID) magnetometry. At low field, we observed vortices that were well separated from their neighbors. In many locations, we observed vortices that carried only part of a flux quantum, with a magnitude that varied continuously with temperature. We interpret these features as vortices with non-quantized magnetic flux, sometimes called fractional or partial vortices whose magnitude is determined by the temperature-dependent parameters of a multiband superconductor. We further characterize the mobility and manipulability of the fractional vortices.

*This work was primarily supported by the Department of Energy, Office of Science, Basic Energy Sciences, Materials Sciences and Engineering Division, under Contract No. DE- AC02-76SF00515. E.B. was supported by the Swedish Research Council Grants No. 2016-06122, 2018-03659. V.G. was supported by DFG GR 4667/1 and the Würzburg-Dresden Cluster of Excellence on Complexity and Topology in Quantum Matter-ct.qmat (EXC 2147, Project ID 390858490).

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Presenters

  • Yusuke Iguchi

    • Stanford University
    • Stanford university
    • Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory

Authors

  • Yusuke Iguchi

    • Stanford University
    • Stanford university
    • Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory

  • Ruby A Shi

    • Stanford University
    • Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory

  • Kunihiro Kihou

    • National Institute of Advanced Industrial Science and Technology (AIST)
    • AIST

  • Chul-Ho Lee

    • National Institute of Advanced Industrial Science and Technology (AIST)
    • AIST

  • Mats Barkman

    • KTH Royal Institute of Technology

  • Andrea Benfenati

    • KTH Royal Institute of Technology

  • Vadim Grinenko

    • Tsung-Dao Lee Institute, Shanghai Jiao Tong University
    • Technische Universitat Dresden, Dresden, Germany
    • TU Dresden

  • Egor Babaev

    • KTH Royal Institute of Technology

  • Kathryn A Moler

    • Stanford University
    • Stanford Univ
    • Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory