Nodal Superconductivity in Single-crystalline Tetragonal FeS: A Muon Spin Relaxation and Rotation Study

ORAL

Abstract

We report the muon spin relaxation and rotation (μSR) measurements on hydrothermal grown singlecrystalline tetraganol FeS, which is much debated recently on its magnetic state and superconducting gap symmetry. We measured the zero-field relaxation rate λZF down to 0.025 K, which saturates below Tsat ≈ 4 K. The temperature dependence of λZF can be well explained by thermal excitation of electronic fluctuations, demonstrating FeS is a paramagnet. Our transverse field measurements give the in-plane penetration depth λab(0) = 312(5) nm. The linear low-T dependence of depolarization rate σsc ∝ λab-2 reveals the nodal superconductivity in tetragonal FeS. The s+d-waves model gives the best fit to our data at the fields we applied (μ0H = 7.5 mT, 30
mT, and 75 mT). The normalized superfluid density versus normalized temperature for different field collapse on the same curve, indicating the superconducting gap structure is independent of field up to 75 mT.

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Presenters

  • Cheng Tan

    State Key Laboratory of Surface Physics and Department of Physics, Fudan University, State Key Laboratory of Surface Physics, Department of Physics, Fudan University, Physics, Fudan University

Authors

  • Cheng Tan

    State Key Laboratory of Surface Physics and Department of Physics, Fudan University, State Key Laboratory of Surface Physics, Department of Physics, Fudan University, Physics, Fudan University

  • Tianping Ying

    Fudan University, Physics, Fudan University

  • Lei Shu

    State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Fudan University, Department of Physics, Fudan University, State Key Laboratory of Surface Physics, Department of Physics, Fudan University, Physics, Fudan University