Phonon Softening and Instability of MgCNi$_{3}$; Phonon dispersion measurements

ORAL

Abstract

Inelastic x-ray scattering from a single crystal MgCNi$_{3}$ was carried to determine phonon dispersion on the three major axes. Our results agree qualitatively with the most recent theoretical calculation. The dispersion shows quite strong softening of the longitudinal acoustic (LA) modes toward zone boundaries along $\Gamma $-M and $\Gamma $-R. However, phonon instabilities predicted by earlier theories were not observed. Our results would motivate the rethinking of MgCNi$_{3}$ superconductivity based on unstable phonons.

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Authors

  • Hawoong Hong

    • Argonne National Laboratory
    • Argonne National Lab

  • Mary Upton

    • Argonne National Laboratory

  • Ayman Said

    • Argonne National Laboratory

  • Hyun-Sook Lee

    • Pohang University of Science and Technology

  • Sung-Ik Lee

    • Sogang University

  • Ruqing Xu

    • University of Illiniois at Urbana-Champaign
    • University of Illinois at Urbana-Champaign

  • Tai-Chang Chiang

    • University of Illinois at Urbana-Champaign