Predicted reentrant melting of dense hydrogen at ultra-high pressures

Abstract

The phase diagram of hydrogen is one of the most important challenges in high-pressure physics and astrophysics. Especially, the melting of dense hydrogen is complicated by dimer dissociation, metallization and nuclear quantum effect of protons, which together lead to a cold melting of dense hydrogen when above 500 GPa. Nonetheless, the variation of the melting curve at higher pressures is virtually uncharted. Here we report that using ab initio molecular dynamics and path integral simulations based on density functional theory, a new atomic phase is discovered, which gives an uplifting melting curve of dense hydrogen when beyond 2 TPa, and results in a reentrant solid-liquid transition before entering the Wigner crystalline phase of protons. The findings greatly extend the phase diagram of dense hydrogen, and put metallic hydrogen into the group of alkali metals, with its melting curve closely resembling those of lithium and sodium. [With erratum. And the structural information of C2221 phase is also provided in this version]

28 pages, 10 figures, with erratum and structural details

References in corpus (6)

• A superconductor to superfluid phase transition in liquid metallic hydrogen
• Nuclear Quantum Effects and Nonlocal Exchange-Correlation Functionals Applied to Liquid Hydrogen at High Pressure
• Room-Temperature Structures of Solid Hydrogen at High Pressures
• Distinct metallization and atomization transitions in dense liquid hydrogen
• Lattice stability and high pressure melting mechanism of dense hydrogen up to 1.5 TPa
• Accelerating ab initio path integral molecular dynamics with multilevel sampling of potential surface

Cited by in corpus (10)

• Thermodynamic anomalies and three distinct liquid-liquid transitions in warm dense liquid hydrogen
• Prediction of Stable Ground-State Lithium Polyhydrides under High Pressures
• Optical properties of dense lithium in electride phases by first-principles calculations
• Prediction of a Mobile Solid State in Dense Hydrogen under High Pressures
• Simultaneous Superconducting and Topological Properties in Mg-Li Electrides at High Pressures
• Full Temperature-Dependent Potential and Anharmonicity in Metallic Hydrogen: Colossal NQE and the Consequences
• Pressure induced Structure Change and Anomalies in Thermodynamic Quantities and Transport Properties in Liquid Lithium Hydride
• Prediction of Superionic State in LiH2 at Conditions Enroute to Nuclear Fusion
• Organic compounds in metallic hydrogen
• Appraising the absolute limits of nanotubes and nanospheres to preserve high-pressure materials