Effect of the in-plane magnetic field on the neutron spin resonance in optimally doped FeSe0.4Te0.6 and BaFe1.9Ni0.1As2 superconductors

ORAL

Abstract

We use inelastic neutron scattering to study the effect of an in-plane magnetic field on the magnetic resonance in optimally doped superconductors FeSe0.4Te0.6 (Tc = 14 K) and BaFe1.9Ni0.1As2 (Tc = 20 K). While the magnetic field up to 14.5 T does not change the energy of the resonance, it partially suppresses Tc and the corresponding superconductivity-induced intensity gain of the mode. However, we find no direct evidence for the field-induced spin-1 Zeeman splitting of the resonance. Therefore it is still unclear if the resonance is the long-sought singlet-triplet excitation directly coupled to the superconducting electron Cooper pairs.

*This work was supported by CAS, 973 program and US DOE, BES.

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Authors

  • Xingye Lu

    • Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China

  • Shiliang Li

    • Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China

  • Meng Wang

    • Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China

  • Huiqian Luo

    • Laboratory for Superconductivity, Institute of Physics
    • Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China

  • Pengcheng Dai

    • University of Tennessee
    • Department of Physics and Astronomy, The University of Tennessee, Knoxville,Tennessee 37996-1200, USA