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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).

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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