Evidence for multi-gap nodal superconductivity in FeS by penetration depth measurements.

ORAL

Abstract

We report measurements of London penetration depth and magnetization on single crystals of FeS superconductor with a transition temperature of 4 K. From magnetization measurements, FeS was confirmed to be a type-II superconductor with Hc1(0) = 58 ± 4 Oe, λab(0) = 900 ± 90 nm, and ξ(0) = 90 ± 12 nm. The low temperature (T < 0.3Tc) behavior of penetration depth deviates from a conventional exponential predicted by BCS theory and fits well to a power law with an exponent n = 2.2 ± 0.1 which suggests the presence of nodes in the system. The superfluid density was calculated and was found to fit best to a multi-gap s+d wave model with the d-wave gap having slightly larger weight (p=0.6). Δ(0)/kBTc for the d-wave gap is higher than that of the BCS weak coupling model, implying strong coupling in the system. This gap structure is consistent with recent theoretical and experimental studies.

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Presenters

  • Sujith Kunniniyil Sudheesh

    Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore

Authors

  • Sujith Kunniniyil Sudheesh

    Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore

  • Tianping Ying

    State Key Laboratory of Surface Physics, Department of Physics and Laboratory of Advanced Materials, Fudan University, Shanghai, China

  • Xiaofang Lai

    School of Physics and Optoelectronic Engineering, Guangdong University of Technology, Guangdkong, China

  • Jian-Xin Zhu

    Theoretical Division, Los Alamos National Laboratory, Los Alamos National Laboratory, Theoretical Division and Center for Integrated Nanotechnologies, Los Alamos National Laboratory, T4-PHYS OF CONDENSED MATTER & COMPLEX SYS, Los Alamos National Laboratory, Los aAlamos, USA, CINT, Los Alamos National Laboratory, Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos National Laboratory,

  • Shiyan Li

    State Key Laboratory of Surface Physics, Department of Physics and Laboratory of Advanced Materials, Fudan University, Shanghai, China

  • Ee Min Chia

    Nanyang Technological University, Department of Physics and Applied Physics, Nanyang Technological University, Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, School of Physical and Mathematical Sciences, Nanyang Technological University