Queyroux J-A, Hernandez J-A, Weck G, Ninet S, Plisson T, Klotz S, Garbarino G, Guignot N, Mezouar M, Hanfland M, Itié J-P, Datchi F
Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie (IMPMC), Sorbonne Université, CNRS UMR 7590, Muséum National d'Histoire Naturelle, 4 place Jussieu, F-75005 Paris, France.
Commissariat à l'Energie Atomique (CEA), Direction des Applications Militaires (DAM), DAM Ile-de-France (DIF), F-91297 Arpajon, France.
Phys Rev Lett. 2020 Nov 6;125(19):195501. doi: 10.1103/PhysRevLett.125.195501.
The phase diagram and melting curve of water ice is investigated up to 45 GPa and 1600 K by synchrotron x-ray diffraction in the resistively and laser heated diamond anvil cell. Our melting data evidence a triple point at 14.6 GPa, 850 K. The latter is shown to be related to a first-order solid transition from the dynamically disordered form of ice VII, denoted ice VII^{'}, toward a high-temperature phase with the same bcc oxygen lattice but larger volume and higher entropy. Our experiments are compared to ab initio molecular dynamics simulations, enabling us to identify the high-temperature bcc phase with the predicted superionic ice VII^{''} phase [J.-A. Hernandez and R. Caracas, Phys. Rev. Lett. 117, 135503 (2016).PRLTAO0031-900710.1103/PhysRevLett.117.135503].
利用电阻加热和激光加热的金刚石对顶砧中的同步辐射X射线衍射，研究了水冰的相图和熔化曲线，压力范围高达45吉帕，温度范围高达1600开尔文。我们的熔化数据证明了在14.6吉帕、850开尔文处存在一个三相点。结果表明，后者与冰VII的动态无序形式（记为冰VII′）向具有相同体心立方氧晶格但体积更大、熵更高的高温相的一级固体转变有关。我们的实验与从头算分子动力学模拟进行了比较，使我们能够将高温体心立方相与预测的超离子冰VII″相[J.-A. 埃尔南德斯和R. 加拉卡斯，《物理评论快报》117, 135503 (2016年)。PRLTAO0031 - 900710.1103/PhysRevLett.117.135503] 进行识别。
