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arXiv · 2203.12897

Same and interconvertible high-pressure ice phases

Aleks Reinhardt·Mandy Bethkenhagen·Federica Coppari·Marius Millot·Sebastien Hamel·Bingqing Cheng
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Abstract

Most experimentally known high-pressure ice phases have a body-centred cubic (bcc) oxygen lattice. Our atomistic simulations show that, amongst these bcc ice phases, ices VII, VII' and X are the same thermodynamic phase under different conditions, whereas superionic ice VII'' has a first-order phase boundary with ice VII'. Moreover, at about 300 GPa, ice X transforms into the Pbcm phase with a sharp structural change but no apparent activation barrier, whilst at higher pressures the barrier gradually increases. Our study thus clarifies the phase behaviour of the high-pressure insulating ices and reveals peculiar solid-solid transition mechanisms not known in other systems.

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Aleks Reinhardt, Mandy Bethkenhagen, Federica Coppari, Marius Millot, Sebastien Hamel, Bingqing Cheng. 2022-03-24. Same and interconvertible high-pressure ice phases. https://doi.org/10.1038/s41467-022-32374-1

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