%0 Journal Article
%A Husband, Rachel
%A Liermann, Hanns-Peter
%A McHardy, James
%A Mcwilliams, Ryan Stewart
%A Goncharov, Alexander
%A Prakapenka, Vitali
%A Edmund, Eric
%A Chariton, Stella
%A Konopkova, Zuzana
%A Strohm, Cornelius
%A Sanchez-Valle, Carmen
%A Frost, Mungo
%A Andriambariarijaona, Leon
%A Appel, Karen
%A Baehtz, Carsten
%A Ball, Orianna
%A Briggs, Richard
%A Buchen, Johannes
%A Cerantola, Valerio
%A Choi, Jinhyuk
%A Coleman, Amy
%A CYNN, HYUNCHAE
%A Dwivedi, Anand
%A Graafsma, Heinz
%A Hwang, Huijeong
%A Koemets, Egor
%A Laurus, Torsten
%A Lee, Yongjae
%A Li, Xinyang
%A Marquardt, Hauke
%A Mondal, Anshuman
%A Nakatsutsumi, Motoaki
%A NINET, Sandra
%A Pace, Edward
%A Pépin, Charles
%A Prescher, Clemens
%A Stern, Stephan
%A Sztuk-Dambietz, Jolanta
%A Zastrau, Ulf
%A McMahon, Malcolm
%T Phase transition kinetics of superionic H<sub>2</sub>O ice phases revealed by MHz XFEL heating experiments
%J Nature Communications
%V 15
%N 1
%@ 2041-1723
%C [London]
%I Nature Publishing Group UK
%M PUBDB-2024-05368
%P 8256
%D 2024
%Z We acknowledge support from the Deutsche For-schungsgemeinschaft (DFG) Research Unit FOR 2440 grants SA2585/5-1 (R.J.H, A.M., C.S.V., and H.P.L) and AP262/2-2 (K.A.).
%X H2O transforms to two forms of superionic (SI) ice at high pressures and temperatures, which contain highly mobile protons within a solid oxygen sublattice. Yet the stability field of both phases remains debated. Here, we present the results of an ultrafast X-ray heating study utilizing MHz pulse trains produced by the European X-ray Free Electron Laser to create high temperature states of H2O, which were probed using X-ray diffraction during dynamic cooling. We confirm an isostructural transition during heating in the 26-69 GPa range, consistent with the formation of SI-bcc. In contrast to prior work, SI-fcc was observed exclusively above  50 GPa, despite evidence of melting at lower pressures. The absence of SI-fcc in these runs is attributed to short heating timescales and the pressure-temperature path induced by the pump-probe heating scheme in which H2O was heated above its melting temperature before the observation of quenched crystalline states, based on the earlier theoretical prediction that SI-bcc nucleates more readily from the fluid than SI-fcc. Our results may have implications for the stability of SI phases in ice-rich planets, for example during dynamic freezing, where the preferential crystallization of SI-bcc may result in distinct physical properties across mantle ice layers.
%F PUB:(DE-HGF)16
%9 Journal Article
%$ pmid:39313509
%U <Go to ISI:>//WOS:001320768800004
%R 10.1038/s41467-024-52505-0
%U https://bib-pubdb1.desy.de/record/612515