Pressure-induced collapsed-tetragonal phase in SrCo$_{2}$As$_{2}$ at ambient temperature

ORAL

Abstract

Our recent high-energy (HE) high-pressure (HP) x-ray powder diffraction measurements on tetragonal (T) SrCo$_{2}$As$_{2}$ have revealed a first-order pressure-induced structural phase transition to a collapsed tetragonal (cT) phase with a reduction in $c$ by -7.9\% and the $c/a$ ratio by -9.9\%. The T and cT phases coexist for applied pressures 6~GPa to 18~GPa at 7~K. Resistance measurements up to 5.9 GPa and down to 1.8 K signatures likely associated with the cT phase above 5.5 GPa and found no evidence for superconductivity. Neutron diffraction data show no evidence of magnetic order up to 1.1 GPa. Here, we show that the T to cT transition occurs around 6.8 GPa at ambient temperature, and that the transition is nearly temperature-independent from 300~K down to 7~K, which indicates a steep $p-T$ phase line.\\ Work at Ames Lab. was supported by US DOE, BES, DMSE under DE-AC02-07CH11358. This research used resources at the APS and ORNL, US DOE, SC, User Facilities.

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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 Lab., Dept. of Physics and Astronomy, Iowa State Univ.

  • Udhara Kaluarachchi

    Ames Lab., Dept. of Physics and Astronomy, Iowa State Univ., Iowa State University/ Ames LabLaboratory

  • B. G. Ueland

    Ames National Laboratory, Ames Lab., Dept. of Physics and Astronomy, Iowa State Univ., Ames Laboratory, Dept. of Physics and Astronomy, Iowa State University

  • A. Pandey

    Ames Lab., Dept. of Physics and Astronomy, Iowa State Univ., Ames Laboratory, Dept. of Physics and Astronomy, Iowa State University, Ames Laboratory, Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, Ames Lab. & Iowa State Univ., Ames, IA, 50011

  • Y. Lee

    Ames Lab., Dept. of Physics and Astronomy, Iowa State Univ., Ames Laboratory, U.S. DOE and Dept. of Physics and Astronomy, Iowa State University

  • Valentin Taufour

    The Ames Laboratory and Iowa State University, Ames Lab., Dept. of Physics and Astronomy, Iowa State Univ., Iowa State University/ Ames Laboratory, Ames Laboratory / Iowa State University, Ames, IA 50011, USA

  • A. Sapkota

    Ames Lab., Dept. of Physics and Astronomy, Iowa State Univ., Ames Laboratory, Dept. of Physics and Astronomy, Iowa State University, Ames Lab. & Iowa State Univ., Ames, IA, 50011

  • K. Kothapalli$^{*}$

    Ames Lab., Dept. of Physics and Astronomy, Iowa State Univ., $^*$Ames Laboratory, Dept. of Phys. and Astro., Iowa State University, IA, USA; $^+$Argonne National Laboratory, Argonne, IL, USA

  • N. S. Sangeetha

    Ames Lab., Dept. of Physics and Astronomy, Iowa State Univ.

  • Sergey L. Bud'ko

    Ames Laboratory, U.S. DOE and Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA, Ames Lab., Dept. of Physics and Astronomy, Iowa State Univ., Ames Laboratory/Iowa State University, Iowa State University/ Ames Laboratory, Ames Laboratory, Dept. of Phys. and Astro, Iowa State Univ.

  • B. N. Harmon

    Ames Lab., Dept. of Physics and Astronomy, Iowa State Univ., Ames Laboratory, U.S. DOE and Dept. of Physics and Astronomy, Iowa State University

  • Paul C. Canfield

    The 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 Lab., Dept. of Physics and Astronomy, Iowa State Univ., Iowa State University/ Ames Laboratory, Ames Laboratory, Dept. of Phys. and Astro, Iowa State Univ., Ames Laboratory and Dept of Physics and Astronomy, Iowa State University

  • David C. Johnston

    Ames Lab., Dept. of Physics and Astronomy, Iowa State Univ., Ames Laboratory, Dept. of Physics and Astronomy, Iowa State University, Ames Laboratory, Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, Ames Lab. & Iowa State Univ., Ames, IA, 50011, Iowa State Univ, Ames Laboratory, Dept. of Phys. and Astro, Iowa State Univ.

  • A. Kreyssig$^{*}$

    Ames Laboratory, U.S. DOE and Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA, Ames Lab., Dept. of Physics and Astronomy, Iowa State Univ., Ames Laboratory, Dept. of Physics and Astronomy, Iowa State University, Ames Lab. & Iowa State Univ., Ames, IA, 50011, $^*$Ames Laboratory, Dept. of Phys. and Astro., Iowa State University, IA, USA; $^+$University of Missouri Research Reactor, MO, USA

  • Alan Goldman

    Ames Laboratory, U.S. DOE and Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA, Ames Lab., Dept. of Physics and Astronomy, Iowa State Univ., Ames Laboratory, Dept. of Physics and Astronomy, Iowa State University, Ames Lab. & Iowa State Univ., Ames, IA, 50011, Iowa State University

  • G. Fabbris

    Argonne Natl. Lab.

  • Y. Feng

    Argonne Natl. Lab.

  • L. S. I. Veiga

    Argonne Natl. Lab.

  • A. M. dos Santos

    Oak Ridge Natl. Lab.