Spectroscopic evidence for pre-formed heavy electron pairs and novel pairing mechanism in CeCoIn<sub>5</sub> (Part 1/2)

ORAL

Abstract

The heavy-fermion compound CeCoIn5 shows unconventional superconductivity (Tc=2.3 K) with dx2-y2–wave pairing symmetry[1]. Despite evidence for pseudogap in the normal state[2], their spectroscopic nature remains to be unraveled. Here, we present results from planar tunneling spectroscopy measurements on CeCoIn5 along [001], [100], and [110] directions. While the nodal junction exhibits only a zero-bias conductance peak, the non-nodal junctions show sharp double peaks corresponding to the superconducting gap. Interestingly, they evolve continuously crossing the Tc, merging into a single broad peak at Tp=5K. From quantitative analyses of the conductance spectra, we have found that the gap persistent in the normal state originates from the formation of heavy electron pairs that condense into a coherent state below Tc. We will discuss the implications of our findings in the context of other measurement results in the literature along with the underlying pairing mechanism.

[1]Park,et al,PRL100,177001(2008);Thompson,et al,JPSJ 81,011002(2012).
[2]Ernst,et al,Phys. Stat. Sol. B 247,624(2010);Fasano,et al,Physica B 536,798(2018).

*Supported by NSF/DMR-1704712(FSU),DOE, Office of BES, & Division of MSE(LANL), NSF/DMR-1810310(UC-San Diego),and NSF/DMR-1644779 & the State of Florida (NHMFL).

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Presenters

  • Keshav Shrestha

    • Natl High Magnetic Field Lab
    • National High Magnetic Field Laboratory
    • Idaho National Laboratory

Authors

  • Keshav Shrestha

    • Natl High Magnetic Field Lab
    • National High Magnetic Field Laboratory
    • Idaho National Laboratory

  • Shengzhi Zhang

    • Florida State University
    • National High Magnetic Field Lab, Florida State University

  • Laura Greene

    • National High Magnetic Field Laboratory
    • National High Magnetic Field Lab, Florida State University

  • Joe D Thompson

    • Los Alamos National Laboratory
    • Los Alamos Natl Lab

  • You Lai

    • Florida State University
    • Los Alamos National Laboratory
    • Florida State Univ

  • Ryan Baumbach

    • National High Magnetic Field Laboratory/Florida State University
    • MagLab Tallahassee
    • National High Magnetic Field Laboratory
    • National High Magnetic Field Lab, Florida State University
    • Florida State Univ
    • Natl High Magnetic Field Lab
    • National High Magnetic Field Laboratory, Florida State University
    • Physics, NHMFL, Florida State University

  • Kalyan Sasmal

    • Department of Physics, University of California, San Diego
    • University of California, San Diego
    • Physics, University of California, San Diego

  • M Brian Maple

    • Department of Physics, University of California, San Diego
    • UCSD
    • University of California, San Diego
    • physics, University of Califormia, San Diego
    • Departement of Physics, University fo California, San Diego
    • Physics, University of California, San Diego

  • Wan Kyu Park

    • National High Magnetic Field Laboratory
    • National High Magnetic Field Lab, Florida State University