The non-magnetic collapsed tetragonal phase of CaFe$_{2}$As$_{2}$ and superconductivity in the iron pnictides

ORAL

Abstract

The relationship between antiferromagnetic spin fluctuations and superconductivity has become a central topic of research in studies of superconductivity in the iron pnictides. We present unambiguous evidence of the absence of magnetic fluctuations in the non-superconducting collapsed tetragonal phase of CaFe$_{2}$As$_{2}$ via inelastic neutron scattering time-of-flight data, which is consistent with the view that spin fluctuations are a necessary ingredient for unconventional superconductivity in the iron pnictides. We demonstrate that the collapsed tetragonal phase of CaFe$_{2}$As$_{2}$ is non-magnetic, and discuss this result in light of recent reports of high-temperature superconductivity in the collapsed tetragonal phase of closely related compounds.

*Work at the Ames Laboratory was supported by the Department of Energy, Basic Energy Sciences. Work at ORNL's Spallation Neutron Source was sponsored by the Scientific User Facilities Division, Office of Basic Energy Sciences.

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Authors

  • J.H. Soh

    • Ames Laboratory/ Iowa State University

  • Gregory S. Tucker

    • Ames Laboratory and Department of Physics \& Astronomy, Iowa State University
    • Ames Laboratory/ Iowa State University
    • Ames Laboratory, Dept. of Physics and Astronomy, Iowa State University

  • D.K. Pratt

    • NCNR, NIST, MD
    • National Institute of Standards and Technology

  • D.L. Abernathy

    • Oak Ridge National Laboratory
    • Oak Ridge National Lab
    • Quantum Condensed Matter Division, Oak Ridge National Laboratory

  • M.B. Stone

    • Oak Ridge National Laboratory

  • Sheng Ran

    • Iowa State University, Ames Lab
    • Ames Laboratory/ Iowa State University
    • The Ames Laboratory, Ames, IA 50011, USA
    • Ames Lab, Department of Physics, Iowa State University

  • S.L. Bud'ko

    • Ames Laboratory
    • Ames Laboratory, US DOE, Iowa State University, Ames, Iowa 50011, U.S.A.
    • Iowa State University, Ames Lab
    • Ames Laboratory/ Iowa State University
    • The Ames Laboratory, Ames, IA 50011, USA
    • The Ames Laboratory, Iowa State University, Ames, USA
    • Ames Laboratory and Dept. of Physics and Astronomy, Iowa State University

  • Paul C. Canfield

    • Ames Laboratory, US DOE, Iowa State University, Ames, Iowa 50011, U.S.A.
    • Iowa State University, Ames Lab
    • Ames Laboratory/ Iowa State University
    • Iowa State University
    • Ames Laboratory
    • Iowa State Univ
    • Ames Laboratory and Dept. of Physics, Iowa State University
    • The Ames Laboratory, Ames, IA 50011, USA
    • Ames Lab, Department of Physics, Iowa State University
    • The Ames Laboratory, Iowa State University, Ames, USA
    • Ames Laboratory and Dept. of Physics and Astronomy, Iowa State University

  • Andreas Kreyssig

    • Ames Laboratory and Iowa State University
    • Ames Lab., Iowa State Univ., IA
    • Ames Laboratory/ Iowa State University
    • Iowa State University
    • Ames Laboratory, Dept. Physics Astronomy, Iowa State University
    • The Ames Laboratory, Iowa State University, Ames, USA
    • Ames Laboratory and Dept. of Physics and Astronomy, Iowa State University

  • Robert J. McQueeney

    • Ames Laboratory and Iowa State University
    • Ames Lab. Iowa State Univ., IA
    • Ames Laboratory/ Iowa State University
    • Ames Laboratory and Dept. of Physics and Astronomy, Iowa State University
    • Ames Laboratory, U.S. DOE; Department of Physics and Astronomy, Iowa State University

  • Alan I. Goldman

    • Ames Laboratory and Iowa State University
    • Ames Lab., Iowa State Univ., IA
    • Ames Laboratory/ Iowa State University
    • Ames Laboratory and Dept. of Physics and Astronomy, Iowa State University