High- Tc superconductivity in CaKFe4As4 in absence of nematic fluctuations

W. L. Zhang, W. R. Meier, T. Kong, P. C. Canfield, G. Blumberg

Research output: Contribution to journalArticlepeer-review

18 Scopus citations


We employ polarization-resolved Raman spectroscopy to study the multiband stoichiometric Tc=35 K superconductor CaKFe4As4. We do not detect Pomeranchuk-like electronic nematic fluctuations which were universally observed in the XY(B2g) symmetry Raman response for most families of the Fe-based superconductors. In the superconducting state we observe, consistent with a nodeless order parameter, a full spectral weight suppression at low energies and the emergence of a composite pair-breaking coherence feature at energies between 12 and 20 meV. We analyze the superconductivity-induced phonon self-energy effects and give an estimation for the electron-phonon coupling constant λΓ=0.0015 which is insufficient to provide attraction for high-Tc pairing.

Original languageEnglish (US)
Article number140501
JournalPhysical Review B
Issue number14
StatePublished - Oct 10 2018
Externally publishedYes

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics


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