Collapsed tetragonal phase in SrCo$_{2}$As$_{2}$ under high pressure

ORAL

Abstract

SrCo$_{2}$As$_{2}$ possesses the same tetragonal ThCr$_{2}$Si$_{2}$ structure as the $A$Fe$_{2}$As$_{2}$ ($A \quad =$ Ca, Sr, Ba) family of high-temperature superconductors but does not manifest magnetic order or superconductivity down to a temperature of 1.8 K. Nevertheless, inelastic neutron scattering data show the presence of magnetic fluctuations peaked at a wavevector of (1/2 1/2 1), which corresponds to the stripe antiferromagnetic propagation vector found for $A$Fe$_{2}$As$_{2}$. Here, we present evidence from high-energy x-ray diffraction experiments which show that SrCo$_{2}$As$_{2}$ undergoes a transition to a collapsed-tetragonal phase characterized by a 10{\%} reduction of the $c$-lattice parameter for an applied pressure of 5 GPa at 7 K. This fascinating result opens another path for studying the role of magnetic ordering, spin fluctuations, and magnetoelastic coupling in the development of superconductivity in the Fe-pnictides and related materials. -- Work at Ames Laboratory was supported by US DOE, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering under Contract No. DE-AC02-07CH11358. This research used resources of the Advanced Photon Source, a US DOE, Office of Science User Facility.

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Authors

  • W.T. Jayasekara

    • Ames Laboratory U.S. DOE and Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA
    • Ames Laboratory US DOE, Department of Physics and Astronomy, Iowa State University

  • B.G. Ueland

    • Ames Laboratory U.S. DOE and Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA
    • Ames Laboratory, Dept. of Physics and Astronomy, Iowa State University

  • A. Kreyssig

    • Ames Laboratory U.S. DOE and Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA
    • Ames Laboratory US DOE, Department of Physics and Astronomy, Iowa State University

  • Abhishek Pandey

    • Ames Laboratory U.S. DOE and Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA

  • N.S. Sangeetha

    • Ames Laboratory U.S. DOE and Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA
    • Ames Laboratory US DOE, Department of Physics and Astronomy, Iowa State University

  • G. Fabbris

    • Argonne National Lab/Washington University in St. Louis
    • Argonne National Lab./Washington University in St. Louis
    • Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, USA

  • Yejun Feng

    • Argonne National Laboratory
    • Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, USA

  • D. Haskel

    • Argonne National Lab
    • Argonne National Laboratory
    • Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, USA

  • D.C. Johnston

    • Ames Laboratory U.S. DOE and Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA
    • Ames Laboratory US DOE, Department of Physics and Astronomy, Iowa State University

  • A.I. Goldman

    • Ames Laboratory and Iowa State University
    • Ames Laboratory U.S. DOE and Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA
    • Ames Laboratory US DOE, Department of Physics and Astronomy, Iowa State University