High-Tc superconductivity in CaKFe4 As4 in absence of nematic fluctuations

Zhang, W.-L.; Meier, William; Kong, Tai; Canfield, Paul; Canfield, Paul; Blumberg, G.

High-Tc superconductivity in CaKFe4 As4 in absence of nematic fluctuations

File

IS_J_9774.pdf (772.11 KB)

Date

2018-10-10

Authors

Zhang, W.-L.

Meier, William

Kong, Tai

Canfield, Paul

Blumberg, G.

Authors

Person

Canfield, Paul

Distinguished Professor

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Ames National Laboratory

Ames National Laboratory is a government-owned, contractor-operated national laboratory of the U.S. Department of Energy (DOE), operated by and located on the campus of Iowa State University in Ames, Iowa.

For more than 70 years, the Ames National Laboratory has successfully partnered with Iowa State University, and is unique among the 17 DOE laboratories in that it is physically located on the campus of a major research university. Many of the scientists and administrators at the Laboratory also hold faculty positions at the University and the Laboratory has access to both undergraduate and graduate student talent.

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Physics and Astronomy

Physics and astronomy are basic natural sciences which attempt to describe and provide an understanding of both our world and our universe. Physics serves as the underpinning of many different disciplines including the other natural sciences and technological areas.

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Materials Science and Engineering

Materials engineers create new materials and improve existing materials. Everything is limited by the materials that are used to produce it. Materials engineers understand the relationship between the properties of a material and its internal structure — from the macro level down to the atomic level. The better the materials, the better the end result — it’s as simple as that.

Department

Ames National LaboratoryPhysics and AstronomyMaterials Science and Engineering

Abstract

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 λ^Γ=0.0015 which is insufficient to provide attraction for high-Tc pairing.