Lorenzo Monacelli^1*, Michele Casula², Kosuke Nakano³, Sandro Sorella⁴, Francesco Mauri¹

1 Physics Department, University of Rome, Sapienza, Italy

2 Institut de Mineralogie, de Physique des Matériaux et de Cosmochimie, Sorbonne Université, France

3 Japan Advanced Institute of Science and Technology (JAIST), Japan

4 International School for Advanced Studies (SISSA), Trieste, Italy

* Corresponding authors emails: lorenzo.monacelli@uniroma1.it

DOI10.24435/materialscloud:r1-wk [version v1]

Publication date: Feb 16, 2022

How to cite this record

Lorenzo Monacelli, Michele Casula, Kosuke Nakano, Sandro Sorella, Francesco Mauri, Quantum phase diagram of high-pressure hydrogen, Materials Cloud Archive 2022.27 (2022), doi: 10.24435/materialscloud:r1-wk.

Description

The interplay between electron correlation and nuclear quantum effects makes our understanding of elemental hydrogen a formidable challenge. Here, we present the phase diagram of hydrogen and deuterium at low temperatures and high-pressure (P > 300 GPa) by accounting for highly accurate electronic and nuclear enthalpies. We evaluated internal electronic energies by diffusion quantum Monte Carlo, while nuclear quantum motion and anharmonicity have been included by the stochastic self-consistent harmonic approximation. Our results show that the long-sought atomic metallic hydrogen, predicted to host room-temperature superconductivity, forms at 577±10 GPa (640±14 GPa in deuterium). Indeed, anharmonicity pushes the stability of this phase towards pressures much larger than previous theoretical estimates or attained experimental values. Before atomization, molecular hydrogen transforms from a metallic phase III to another metallic structure that is still molecular (phase VI) at 422±40 GPa (442±30 GPa in deuterium). We predict clear-cut signatures in optical spectroscopy and DC conductivity that can be used experimentally to distinguish between the two structural transitions. According to our findings, the experimental evidence of metallic hydrogen has so far been limited to molecular phases. The data uploaded here contains the structural information of the simulated phases of hydrogen and their quantum centroid position as a function of pressure and isotope.

Materials Cloud sections using this data

Files

File name	Size	Description
structures_data.tar.gz MD5md5:5250b8f7f13626d4078407b76f75ffc9	5.4 KiB	The data of all the structures reported in the paper.
readme.txt MD5md5:baa2deac68d241fcbfbb5811a3a99e40	4.2 KiB	A description of each file included in the structures_data.tar.gz file

License

Files and data are licensed under the terms of the following license: Creative Commons Attribution 4.0 International. Any usage of the structure should imply a citation to the work https://arxiv.org/abs/2202.05740v2 or its published version when available.
Metadata, except for email addresses, are licensed under the Creative Commons Attribution Share-Alike 4.0 International license.

External references

Keywords

high-pressure hydrogen C2/c-24 hydrogen C2/c-24 Cmca-12 hydrogen Cmca-12 P62/c-24 hydrogen P62/c-24