Is AgCrSe2 really a phonon-liquid electron-crystal?

ORAL

Abstract

The phonon liquid concept, in which superionic diffusion prevents the propagation of transverse acoustic phonons, has proved a popular view in the hunt for materials with ultra-low thermal conductivity. Recent inelastic neutron scattering results on AgCrSe2 have found a quasielastic signal (QENS) around 2 Å-1, and suppression of the transverse phonons above the superionic transition. The QENS scattering has been attributed to the melting of the Ag lattice and it is observed to increase dramatically above the superionic transition. Now, using polarised inelastic neutron scattering we determine the origin of this QENS below and above the superionic transition. The validity of a phonon-liquid in AgCrSe2 will be discussed in light of these results.

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Presenters

  • Sercan Arslan

    Physics Department, Royal Holloway University of London

Authors

  • Sercan Arslan

    Physics Department, Royal Holloway University of London

  • David J. Voneshen

    ISIS Pulsed Neutron and Muon Source, Science and Technology Facilities Council, ISIS Facility, Rutherford Appleton Laboratory, ISIS Facility, RAL

  • Paul Steffens

    Insitut Laue-Langevin, Institut Laue-Langevin

  • Uthayakumar Sivaperumal

    Physics Department, Royal Holloway University of London

  • Robin S. Perry

    University College London, Physics Department, University College London, UCL, London Centre for Nanotechnology and UCL Centre for Materials Discovery, University College London

  • Jon Goff

    Physics Department, Royal Holloway University of London