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Title: Spin Resonance in the New-Structure-Type Iron-Based Superconductor CaKFe4As4

Journal Article · · Journal of the Physical Society of Japan
 [1];  [1];  [2];  [3]; ORCiD logo [4];  [5];  [6];  [7];  [7];  [7]
  1. Comprehensive Research Organization for Science and Society (CROSS), Ibaraki (Japan)
  2. Japan Atomic Energy Agency, Chiba (Japan); Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)
  3. Hokkaido Univ., Sapporo (Japan)
  4. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  5. J-PARC Center, Japan Atomic Energy Agency (JAEA), Tokai, Ibaraki 319-1195, Japan
  6. IMRA Material R&D Co., Ltd., Aichi (Japan); National Institute of Advanced Industrial Science and Technology (AIST), Ibaraki (Japan)
  7. National Institute of Advanced Industrial Science and Technology (AIST), Ibaraki (Japan)

Here, the dynamical spin susceptibility in the new-structure-type iron-based superconductor CaKFe4As4 was investigated by using a combination of inelastic neutron scattering (INS) measurements and random phase approximation (RPA) calculations. Powder INS measurements show that the spin resonance at Qres = 1.17(1) Å–1, corresponding to the (π,π) nesting wave vector in tetragonal notation, evolves below Tc. The characteristic energy of the spin resonance Eres = 12.5 meV is smaller than twice the size of the superconducting gap (2Δ). The broad energy feature of the dynamical susceptibility of the spin resonance can be explained by the RPA calculations, in which the different superconducting gaps on different Fermi surfaces are taken into account. Our INS and PRA studies demonstrate that the superconducting pairing nature in CaKFe4As4 is the s± symmetry.

Research Organization:
Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
Sponsoring Organization:
USDOE
Grant/Contract Number:
AC05-00OR22725
OSTI ID:
1486969
Alternate ID(s):
OSTI ID: 22674091
Journal Information:
Journal of the Physical Society of Japan, Journal Name: Journal of the Physical Society of Japan Journal Issue: 9 Vol. 86; ISSN 0031-9015
Publisher:
Physical Society of JapanCopyright Statement
Country of Publication:
United States
Language:
English

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Effect of gap anisotropy on the spin resonance peak in the superconducting state of iron-based materials journal September 2018
Electronic properties, low-energy Hamiltonian, and superconducting instabilities in CaKFe 4 As 4 journal September 2017
Neutron Spin Resonance in the 112-Type Iron-Based Superconductor journal March 2018
NMR study of the new magnetic superconductor CaK ( Fe 0.951 Ni 0.049 ) 4 As 4 : Microscopic coexistence of the hedgehog spin-vortex crystal and superconductivity journal December 2017
Hedgehog Spin-Vortex Crystal Antiferromagnetic Quantum Criticality in CaK ( Fe 1 − x Ni x ) 4 As 4 Revealed by NMR journal September 2018
Hedgehog spin-vortex crystal stabilized in a hole-doped iron-based superconductor text January 2017
Influence of multiband sign-changing superconductivity on vortex cores and vortex pinning in stoichiometric high- T c   CaKFe 4 As 4 journal April 2018
Effect of gap anisotropy on the spin resonance peak in the superconducting state of iron-based materials text January 2018
Coexisting spin resonance and long-range magnetic order of Eu in EuRbFe 4 As 4 journal July 2019
In-plane magnetic penetration depth of superconducting CaKFe 4 As 4 journal April 2018
Neutron spin resonance in the 112-type iron-based superconductor text January 2018
High- T c superconductivity in CaKFe 4 As 4 in absence of nematic fluctuations journal October 2018
Hedgehog spin-vortex crystal stabilized in a hole-doped iron-based superconductor journal February 2018
Odd and Even Modes of Neutron Spin Resonance in the Bilayer Iron-Based Superconductor CaKFe 4 As 4 journal June 2018
75As NMR Studies of Magnetic Properties of the Magnetic Superconductor CaK(Fe0.967Ni0.033)4As4 journal April 2019