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Raman spectroscopy of hot hydrogen above 200 GPa

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Original languageEnglish
Pages (from-to)495-499
Number of pages5
JournalNature Materials
Volume14
Issue number5
DOIs
StatePublished - May 2015

Abstract

It has been theorized that at high pressure the increased energy of the zero-point oscillations in hydrogen would destabilize the lattice and form a ground fluid state at 0 K (ref. 1). Theory has also suggested that this fluid state, representing a new state of matter, might have unusual properties governed by quantum effects, such as superfluidity or superconductivity(2,3). Here, by combining Raman spectroscopy and in situ high-temperature, high-pressure techniques, we demonstrate that above 200 GPa a new phase transition occurs as temperature is increased, for example 480 K at 255 GPa. If the transformation is interpreted as melting, it would be the lowest melting temperature of any material at these high pressures. We also find a new triple point between phases I and IV and the new phase, and demonstrate that hydrogen retains its molecular character around this point. These data may require a significant revision of the phase diagram of hydrogen above 200 GPa.

    Research areas

  • METALLIC HYDROGEN, MEGABAR PRESSURES, SOLID HYDROGEN, TRANSITION, FLUID

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