Crystal structural variation and phase transition in caesium trichlorocuprate at high pressure

A. G. Christy*, R. J. Angel, J. Haines, S. M. Clark

*Corresponding author for this work

    Research output: Contribution to journalArticle

    9 Citations (Scopus)

    Abstract

    Single-crystal and powder X-ray diffraction experiments, together with Raman spectroscopy, show that the 'hexagonal perovskite' CsCuCl3 undergoes a phase transition at pressures between 1.65 and 3.1 GPa. The transition pressure is strongly dependent upon the form of the sample, being lower in powder specimens than in single crystals. The transition is first order in character and is accompanied by a 1.8% volume charge and a reduction in the length of the c-axis from the six-layer repeat of the room pressure phase to a two-layer repeat. These observations, together with the change in Raman modes at the transition lead us to conclude that the high-pressure structure contains statically disordered Jahn-Teller-distorted CuCl6 octahedra, in contrast to the known high-temperature phase, which contains dynamically disordered distorted octahedra, and the low-pressure, ambient-temperature structure, which displays an ordered array of distorted octahedra.

    Original languageEnglish
    Article number005
    Pages (from-to)3125-3136
    Number of pages12
    JournalJournal of Physics: Condensed Matter
    Volume6
    Issue number17
    DOIs
    Publication statusPublished - 1994

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