Same and interconvertible high-pressure ice phases
arXiv:2203.12897 · doi:10.1038/s41467-022-32374-1
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.
References in corpus (8)
- Well-Tempered Metadynamics: A Smoothly Converging and Tunable Free-Energy Method
- Phase transitions of hybrid perovskites simulated by machine-learning force fields trained on-the-fly with Bayesian inference
- Metadynamics with adaptive Gaussians
- Determination of phase diagrams via computer simulation: Methodology and applications to water, electrolytes and proteins
- Advances in the experimental exploration of water's phase diagram
- Quantum-mechanical exploration of the phase diagram of water
- How Deep Is the Ocean? Exploring the phase structure of water-rich sub-Neptunes
- Proton dynamics in high-pressure ice-VII from density functional theory