Pressure dependence of transverse acoustic phonon energy in ferropericlase across the spin transition

Hiroshi Fukui, Alfred Q.R. Baron, Daisuke Ishikawa, Hiroshi Uchiyama, Yasuo Ohishi, Taku Tsuchiya, Hisao Kobayashi, Takuya Matsuzaki, Takashi Yoshino, Tomoo Katsura

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    3 Citations (Scopus)

    Abstract

    We investigated transverse acoustic (TA) phonons in iron-bearing magnesium oxide (ferropericlase) up to 56 GPa using inelastic x-ray scattering (IXS). The results show that the energy of the TA phonon far from the Brillouin zone center suddenly increases with increasing pressure above the spin transition pressure of ferropericlase. Ab initio calculations revealed that the TA phonon energy far from the Brillouin zone center is higher in the low-spin state than in the high spin state; that the TA phonon energy depend weakly on pressure; and that the energy gap between the TA and the lowest-energy-optic phonons is much narrower in the low-spin state than in the high-spin state. This allows us to conclude that the anomalous behavior of the TA mode in the present experiments is the result of gap narrowing due to the spin transition and explains contradictory results in previous experimental studies.

    Original languageEnglish
    Article number245401
    JournalJournal of Physics Condensed Matter
    Volume29
    Issue number24
    DOIs
    Publication statusPublished - May 17 2017

    Keywords

    • ab initio calculation
    • ferropericlase
    • high pressure
    • inelastic x-ray scattering
    • phonon
    • spin transition

    ASJC Scopus subject areas

    • Materials Science(all)
    • Condensed Matter Physics

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