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