Evolution of soft phonons in FeSe under pressure

ORAL

Abstract

FeSe, as the simplest iron-based superconductor (Fe-SC), is of great interest for furthering our understanding of the Fe-SC materials. It shares a common tetragonal-to-orthorhombic phase transition at 90 K with many of the Fe-SCs, and becomes superconducting at 9 K, but in contrast displays no magnetic order. Previous studies have shown an enhancement of the superconducting transition temperature with increasing pressure, with a maximum of 37 K at approximately 6.3 GPa, and magnetic order concurrent with the structural transition above 1.6 GPa. Here we present IXS measurements of TA phonon dispersion from which we can extract the nematic correlation length. The phonon renormalization effects observed in our experiments have important implications for nematicity and superconductivity. This includes a significant reduction in the phonon softening at the high-pressure structural-magnetic transition and a new phonon hardening effect at the superconducting transition. We will discuss the implications of these results in the context of pressure- and doping-dependence in the Fe-SCs.

*DOE, Office of Basic Energy Sciences, Office of Science, Contract No. DE-SC0006939 (AM & DR)
European Synchrotron Radiation Facility, Grenoble, France
Advanced Photon Source, Argonne National Laboratory, USA

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Presenters

  • Adrian Merritt

    • Physics, University of Colorado, Boulder
    • University of Colorado, Boulder

Authors

  • Adrian Merritt

    • Physics, University of Colorado, Boulder
    • University of Colorado, Boulder

  • Frank Weber

    • Institute for Solid State Physics, Karlsruhe Insitute of Technology

  • Anna Boehmer

    • Institute for Solid State Physics, Karlsruhe Insitute of Technology
    • Karlsruhe Institute of Technology
    • Karlsruhe Institute of Technology; Ames Laboratory

  • Kaushik Sen

    • Institute for Solid State Physics, Karlsruhe Insitute of Technology

  • John-Paul Castellan

    • Institute for Solid State Physics, Karlsruhe Insitute of Technology

  • Thomas Wolf

    • Institute for Solid State Physics, Karlsruhe Insitute of Technology

  • Sofia Michaela Souliou

    • European Synchrotron Radiation Facility

  • Ahmet Alatas

    • Argonne National Laboratory
    • APS, Argonne National Laboratory
    • Advanced Photon Source, Argonne National Laboratory

  • Ayman Said

    • APS, Argonne National Laboratory
    • Advanced Photon Source, Argonne National Laboratory

  • Wenli Bi

    • University of Alabama - Birmingham
    • Univ of Alabama - Birmingham
    • University of Alabama at Birmingham

  • Rafael Fernandes

    • University of Minnesota
    • Physics, University of Minnesota
    • School of Physics and Astronomy, University of Minnesota

  • Dmitry Reznik

    • University of Colorado, Boulder
    • University of Colorado at Boulder
    • Physics, University of Colorado, Boulder