Atomic tunneling in crystalline BaTiS<sub>3</sub>

ORAL

Abstract

BaTiS3 exhibits a hexagonal perovskite structure comprised of columns of sulphur coordinated Ti linked by barium making it a quasi-1D structure. Neutron pair distribution function measurements reveal that the Ti atomic displacement parameters increase with decreasing temperature. This observation suggest proximity to a ferroelectric type phase transition or ground-state dynamic disorder. By combining inelastic x-ray scattering phonon spectroscopy and high-resolution inelastic neutron scattering we find evidence for the dynamic disorder scenario for Ti occupying a double-well potential. These dynamics persist into the quantum regime and atomic tunneling with 0.4 meV tunneling splitting is observed. This unique tunneling dynamics has profound consequences on the thermal conductivity and suggest a novel mechanism for thermal transport design.

*Research supported by the U.S. DOE, Office of Basic Energy Sciences, Materials Sciences and Engineering Division. This research used resources at the Spallation Neutron Source, a DOE Office of Science User Facility operated by the Oak Ridge National Laboratory and at the Advanced Photon Source, a U.S. DOE Office of Science User Facility operated by Argonne National Laboratory under Contract No. DE-AC02-06CH11357

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Presenters

  • Raphael Hermann

    • Oak Ridge National Lab
    • Oak Ridge National Laboratory

Authors

  • Raphael Hermann

    • Oak Ridge National Lab
    • Oak Ridge National Laboratory

  • Michael E Manley

    • Oak Ridge National Laboratory

  • Barry Winn

    • Oak Ridge National Lab
    • Oak Ridge National Laboratory

  • Katharine Page

    • Oak Ridge National Laboratory

  • Austin Minnich

    • Caltech
    • Applied Physics and Mechanical Engineering, California Institute of Technology
    • California Institute of Technology

  • Jaeyun Moon

    • California Institute of Technology

  • Ahmet Alatas

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

  • Jayakanth Ravichandran

    • University of Southern California
    • Mork Family Department of Chemical Engineering and Materials Science, University of Southern California
    • University of Southern California, Los Angeles