IBM Research | My Paper In 300 Seconds: Evidence for supercritical behaviour of high-pressure liquid hydrogen @ibmresearch | Uploaded September 2020 | Updated October 2024, 4 days ago.
Evidence for supercritical behaviour of high-pressure liquid hydrogen
nature.com/articles/s41586-020-2677-y
DOI: 10.1038/s41586-020-2677-y
Hydrogen exhibits unusual behaviors at megabar pressures, with consequences for planetary science, condensed matter physics and materials science. Experiments at such extreme conditions are challenging, often resulting in hard-to-interpret and controversial observations. We present a theoretical study of the phase diagram of dense hydrogen, using machine learning to overcome time and length scale limitations while describing accurately interatomic forces. We reproduce the re-entrant melting behavior and the polymorphism of the solid phase. In simulations based on the machine learning potential we find evidence for continuous metallization in the liquid, as a first-order liquid-liquid transition is pre-empted by freezing. This suggests a smooth transition between insulating and metallic layers in giant gas planets, and reconciles existing discrepancies between experiments as a manifestation of supercritical behavior.
Bingqing Cheng: University of Cambridge, University of Cambridge, University of Cambridge, Trinity College
Guglielmo Mazzola: IBM Research – Zurich
Chris J. Pickard: University of Cambridge, Tohoku University
Michele Ceriotti: École Polytechnique Fédérale de Lausanne
Evidence for supercritical behaviour of high-pressure liquid hydrogen
nature.com/articles/s41586-020-2677-y
DOI: 10.1038/s41586-020-2677-y
Hydrogen exhibits unusual behaviors at megabar pressures, with consequences for planetary science, condensed matter physics and materials science. Experiments at such extreme conditions are challenging, often resulting in hard-to-interpret and controversial observations. We present a theoretical study of the phase diagram of dense hydrogen, using machine learning to overcome time and length scale limitations while describing accurately interatomic forces. We reproduce the re-entrant melting behavior and the polymorphism of the solid phase. In simulations based on the machine learning potential we find evidence for continuous metallization in the liquid, as a first-order liquid-liquid transition is pre-empted by freezing. This suggests a smooth transition between insulating and metallic layers in giant gas planets, and reconciles existing discrepancies between experiments as a manifestation of supercritical behavior.
Bingqing Cheng: University of Cambridge, University of Cambridge, University of Cambridge, Trinity College
Guglielmo Mazzola: IBM Research – Zurich
Chris J. Pickard: University of Cambridge, Tohoku University
Michele Ceriotti: École Polytechnique Fédérale de Lausanne
