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

Abstract

The magnetic response is a state-defining property of superconductors. The magnetic flux penetrates type-II bulk superconductors by forming quantum vortices when the enclosed magnetic flux is equal to the magnetic flux quantum. The flux quantum is the universal quantity that depends only on the ratio of fundamental constants: the electron charge and the Planck constant. This work investigates the vortex state in the hole-overdoped Ba${}_{1-x}$K${}_x$Fe${}_2$As${}_2$ by using scanning superconducting quantum interference device (SQUID) magnetometry. We observed quantum vortices that carry only a fraction of the flux quantum, which vary continuously with temperature. This finding establishes the phenomenon that superconductors support quantum vortices with non-universally quantized magnetic flux. Furthermore, the demonstrations of the mobility of the fractional vortices and the manipulability of their positions open up a route for future fluxonics applications.

19 pages, 9 figures

References in corpus (7)

• Observation of half-height magnetization steps in Sr2RuO4
• Vortex Imaging in the pi-Band of Magnesium Diboride
• Magnetic response of mesoscopic superconducting rings with two order parameters
• A comprehensive scenario of the single crystal growth and doping dependence of resistivity and anisotropic upper critical fields in (Ba${}_{1-x}$K${}_x$)Fe${}_2$As${}_2$ ($0.22\le x\le 1$)
• Observation of superconducting vortices carrying a temperature-dependent fraction of the flux quantum
• The response of small SQUID pickup loops to magnetic fields
• Demonstration of $\mathbb{C}{P}^2$ skyrmions in three-band superconductors by self-consistent solutions to a Bogoliubov-de Gennes model

Cited by in corpus (21)

• Observation of superconducting vortices carrying a temperature-dependent fraction of the flux quantum
• Calorimetric evidence for two phase transitions in Ba${}_{1-\mathrm{x}}$K${}_{\mathrm{x}}$Fe${}_2$As${}_2$ with fermion pairing and quadrupling states
• Observation of nonvolatile magneto-thermal switching in superconductors
• Coreless vortices as direct signature of chiral $d$-wave superconductivity
• Robust and tunable coreless vortices and fractional vortices in chiral $d$-wave superconductors
• Probing Vortex Dynamics in 2D Superconductors with Scanning Quantum Microscope
• Neutron Spin Resonance Near a Lifshitz Transition in Overdoped Ba${}_{0.4}$K${}_{0.6}$Fe${}_2$As${}_2$
• Atomic-scale Frustrated Josephson Coupling and Multi-condensate Visualization in FeSe
• Delocalization of vortex magnetic field near a planar defect
• Tuning Bound States of Symmetry-Breaking Vortices via Unidirectional Charge Density Wave in a Transition-Metal Dichalcogenide Superconductor
• Advanced SQUID-on-lever scanning probe for high-sensitivity magnetic microscopy with sub-100-nm spatial resolution
• Ultrasound evidence for multicomponent superconducting order parameter in Ba${}_{1-x}$K${}_x$Fe${}_2$As${}_2$ with electron quadrupling phase
• Microscopic solutions for vortex clustering in two-band type-1.5 superconductors
• Observation of vortex stripes in UTe${}_2$
• DC-driven separation of fractional flux quanta in two-band superconductors
• Borromean supercounterfluids at finite temperatures
• Fractional vortex array realized at twin boundary in a nematic superconductor
• Microscopic properties of fractional vortices and domain walls in three-band $s+is$ superconductors
• Fractional vorticity, Bogomol'nyi-Prasad-Sommerfield systems and complex structures for the (generalized) spinor Gross-Pitaevskii equations
• Unconventional magnetization in the multiphase superconductor PdBi${}_2$
• Unconventional superconducting correlations in fermionic many-body scars