Evolution of Spin fluctuations in CaFe$_{\mathrm{2}}$As$_{\mathrm{2}}$ with Co-doping.

ORAL

Abstract

Spin fluctuations are an essential ingredient for superconductivity in Fe-based supercondcutors. In Co-doped BaFe$_{\mathrm{2}}$As$_{\mathrm{2}}$, the system goes from the antiferromagnetic (AFM) state to the superconducting (SC) state with Co doping, and the spin fluctuations also evolve from well-defined spin waves with spin gap in the AFM regime to gapless overdamped or diffused fluctuations in the SC regime. CaFe$_{\mathrm{2}}$As$_{\mathrm{2}}$ has a stronger magneto-elastic coupling than BaFe$_{\mathrm{2}}$As$_{\mathrm{2}}$ and no co-existence of SC and AFM region as observed in BaFe$_{\mathrm{2}}$As$_{\mathrm{2\thinspace }}$with Co doping. Here, we will discuss the evolution of spin fluctuations in CaFe$_{\mathrm{2}}$As$_{\mathrm{2}}$ with Co doping.

*Work at the Ames Laboratory was supported by US DOE, Basic Energy Sciences, Division of Material Sciences and Engineering, under contract No. DE-AC02-07CH11358. This research used resources of SNS, a DOE office of science user facility operated by ORNL.

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Authors

  • A. Sapkota

    • Ames Laboratory, Dept. of Physics and Astronomy, Iowa State University

  • Pinaki Das

    • Ames Laboratory, Dept. of Physics and Astronomy, Iowa State University
    • Ames Laboratory, Iowa State University, IA, USA

  • A. E. B\"{o}hmer

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

  • D. L. Abernathy

    • Oak Ridge National Laboratory

  • Paul Canfield

    • Iowa State Univ Ames Laboratory
    • Ames Laboratory/ Iowa State University, Ames, IA 50011, USA
    • Iowa State Univ
    • $^A$Ames Laboratory US DOE, $^B$Department of Physics and Astronomy, $^C$Department of Chemistry, Iowa State University, Ames, Iowa 50011, USA.
    • Iowa State University/ Ames LabLaboratory
    • Ames Lab
    • Ames Laboratory, Dept. of Physics and Astronomy, Iowa State University
    • Ames Laboratory and Dept. of Phys. and Astro., Iowa State University
    • Ames Laboratory and Department of Physics, Iowa State University, Ames, Iowa
    • Iowa State Univ and Ames Laboratory
    • Ames Lab and Department of Physics, Iowa State University, Ames, Iowa

  • A. Kreyssig

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

  • R. J. McQueeney

    • Ames Laboratory, Dept. of Physics and Astronomy, Iowa State University

  • A. I. Goldman

    • Ames Laboratory, Dept. of Physics and Astronomy, Iowa State University