Evidence for multi-gap nodal superconductivity in <i>FeS</i> 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