Hedgehog spin-vortex crystal antiferromagnetic quantum criticality in CaK(Fe<sub>1-x</sub>Ni<sub>x</sub>)<sub>4</sub>As<sub>4</sub> revealed by NMR

ORAL

Abstract

Two degrees of freedom, antiferromagnetism and nematicity, have been observed in most iron-based superconductors (SCs). In contrast to those compounds, the newly discovered SC CaK(Fe1-xNix)4As4 exhibits an antiferromagnetic (AFM) state, called hedgehog spin-vortex crystal (SVC) structure, without the orthorhombic distortion [1,2]. This system provides an opportunity to investigate he relationship between magnetic fluctuation and SC in a system that remains tetragonal. Here, we report an 75As nuclear magnetic resonance (NMR) study of CaK(Fe1-xNix)4As4 (0 ≤ x ≤ 0.049). We will show the experimental evidence which suggests that, based on NMR data [3] , a hedgehog SVC quantum-critical point (QCP) would exist around x = 0 in the normal state, but is avoided due to the onset of superconductivity. We will discuss the relationship of spin fluctuations and superconductivity in this system. Furthermore, the advantage of CaKFe4As4 over other iron-based SCs with QCP will also be discussed.

[1] W. R. Meier, et al., npj Quantum Mater. 3, 5 (2018).
[2] Q. -P, Ding, et al., Phys. Rev. B. 96, 220510(R) (2017).
[3] Q. -P, Ding, et al., Phys. Rev. Lett. 121, 137204 (2018).

*This work is supported by the US DOE, Basic Energy Sciences under Con-tract No. DE-AC02-07CH11358.

–

Presenters

  • Qing-Ping Ding

    • Ames Laboratory, Iowa State University
    • Ames Laboratory
    • Ames Laboratory and Dept. of Phys. and Astro.,, Iowa State Univ.
    • Iowa State University & Ames Lab

Authors

  • Qing-Ping Ding

    • Ames Laboratory, Iowa State University
    • Ames Laboratory
    • Ames Laboratory and Dept. of Phys. and Astro.,, Iowa State Univ.
    • Iowa State University & Ames Lab

  • William Meier

    • Ames Laboratory and Dept. of Physics, Iowa State University
    • Ames Laboratory, Iowa State University
    • Ames Laboratory and Dept. of Phys. and Astro.,, Iowa State Univ.
    • Iowa State University and Ames Laboratory
    • Ames Laboratory & Department of Physics, Iowa State University

  • JINFANG CUI

    • Ames Laboratory and Dept. of Chem., Iowa State Univ.

  • Mingyu Xu

    • Ames Laboratory, Iowa State University
    • Ames Laboratory and Dept. of Phys. and Astro.,, Iowa State Univ.
    • Ames Laboratory & Iowa State University
    • Iowa State University and Ames Laboratory

  • Anna Boehmer

    • Ames Laboratory/Iowa State University
    • Ames Laboratory and Dept. of Phys. and Astro.,, Iowa State Univ.
    • Institut für Festkörperphysik, Karlsruhe Institute of Technology

  • Sergey Budko

    • Iowa State University
    • Department of Physics, Iowa State University, Ames Laboratory, Ames, Iowa 50011, USA
    • Ames Laboratory, Iowa State University
    • Ames Laboratory/Iowa State University
    • Ames Laboratory and Dept. of Phys. and Astro.,, Iowa State Univ.
    • Ames Laboratory and Department of Physics & Astronomy, Iowa State University, Ames, IA 50010, USA
    • Ames Lab & Dept of Physics and Astronomy, Iowa State University
    • Physics, Iowa State University/Ames Laboratory
    • Iowa State University and Ames Laboratory

  • Paul Canfield

    • Ames Laboratory and Dept. of Physics, Iowa State University
    • Ames Laboratory, U.S. DOE, Iowa State University, Ames, Iowa 50011, USA.
    • Ames Laboratory
    • Iowa State University
    • Department of Physics, Iowa State University, Ames Laboratory, Ames, Iowa 50011, USA
    • Ames Laboratory, Iowa State University
    • Ames Laboratory/Iowa State University
    • Iowa State University and Ames Laboratory
    • Ames Laboratory and Iowa State University, Ames, IA, USA
    • Ames Laboratory and Dept. of Phys. and Astro.,, Iowa State Univ.
    • Ames Laboratory and Department of Physics & Astronomy, Iowa State University, Ames, IA 50010, USA
    • Ames Lab & Dept of Physics and Astronomy, Iowa State University
    • Department of Physics & Astronomy, Iowa State University
    • Department of physics and astronomy, Iowa State University/Ames Laboratory
    • Physics, Iowa State University/Ames Laboratory
    • Ames Laboratory & Iowa State University
    • Physics, Iowa State University

  • Yuji Furukawa

    • Ames Laboratory, Iowa State University
    • Department of Physics, Iowa State University, Ames Laboratory, Ames, Iowa 50011, USA
    • Ames Laboratory and Dept. of Phys. and Astro.,, Iowa State Univ.
    • Iowa State University & Ames Lab
    • Ames Lab & Dept of Physics and Astronomy, Iowa State University
    • Iowa State University