imprint:
Springer Science and Business Media LLC, 2022
Published in:Nature Communications
Language:
English
DOI:
10.1038/s41467-022-32374-1
ISSN:
2041-1723
Origination:
Footnote:
Description:
<jats:title>Abstract</jats:title><jats:p>Most experimentally known high-pressure ice phases have a body-centred cubic (bcc) oxygen lattice. Our large-scale molecular-dynamics simulations with a machine-learning potential indicate 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, the transformation between ice X and the P<jats:italic>bcm</jats:italic> phase has 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 ices and reveals peculiar solid–solid transition mechanisms not known in other systems.</jats:p>