Azadi, S;
Singh, R;
Kühne, TD;
(2018)
Nuclear quantum effects induce metallization of dense solid molecular hydrogen.
Journal of Computational Chemistry
, 39
(5)
pp. 262-268.
10.1002/jcc.25104.
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Abstract
We present an accurate computational study of the electronic structure and lattice dynamics of solid molecular hydrogen at high pressure. The band-gap energies of the C2/c, Pc, and P63/mstructures at pressures of 250, 300, and 350 GPa are calculated using the diffusion quantum Monte Carlo (DMC) method. The atomic configurations are obtained from ab initio path-integral molecular dynamics (PIMD) simulations at 300 K and 300 GPa to investigate the impact of zero-point energy and temperature-induced motion of the protons including anharmonic effects. We find that finite temperature and nuclear quantum effects reduce the band-gaps substantially, leading to metallization of the C2/c and Pc phases via band overlap; the effect on the band-gap of the P63/mstructure is less pronounced. Our combined DMC-PIMD simulations predict that there are no excitonic or quasiparticle energy gaps for the C2/c and Pc phases at 300 GPa and 300 K. Our results also indicate a strong correlation between the band-gap energy and vibron modes. This strong coupling induces a band-gap reduction of more than 2.46 eV in high-pressure solid molecular hydrogen. Comparing our DMC-PIMD with experimental results available, we conclude that none of the structures proposed is a good candidate for phases III and IV of solid hydrogen. © 2017 Wiley Periodicals, Inc.
Type: | Article |
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Title: | Nuclear quantum effects induce metallization of dense solid molecular hydrogen |
Open access status: | An open access version is available from UCL Discovery |
DOI: | 10.1002/jcc.25104 |
Publisher version: | https://doi.org/10.1002/jcc.25104 |
Language: | English |
Additional information: | This version is the author accepted manuscript. For information on re-use, please refer to the publisher’s terms and conditions. |
Keywords: | metallic hydrogen, nuclear quantum effects, path‐integral molecular dynamics, Car‐Parrinello molecular dynamics, quantum Monte Carlo |
UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences |
URI: | https://discovery-pp.ucl.ac.uk/id/eprint/10062579 |
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