Nuclear quantum effects induce metallization of dense solid molecular hydrogen

Azadi S, Singh R, Kühne TD (2018)

Publication Type: Journal article

Publication year: 2018

Journal

Journal of Computational Chemistry Wiley-Blackwell

Book Volume: 39

Pages Range: 262-268

Journal Issue: 5

DOI: 10.1002/jcc.25104

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/m structures 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/m structure 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.

Involved external institutions

Imperial College London / The Imperial College of Science, Technology and Medicine GB United Kingdom (GB) University of Delhi IN India (IN) Universität Paderborn DE Germany (DE)

How to cite

APA:

Azadi, S., Singh, R., & Kühne, T.D. (2018). Nuclear quantum effects induce metallization of dense solid molecular hydrogen. Journal of Computational Chemistry, 39(5), 262-268. https://doi.org/10.1002/jcc.25104

MLA:

Azadi, Sam, Ranber Singh, and Thomas D. Kühne. "Nuclear quantum effects induce metallization of dense solid molecular hydrogen." Journal of Computational Chemistry 39.5 (2018): 262-268.

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