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arXiv · 1911.06135

Energy gap closure of crystalline molecular hydrogen with pressure

Vitaly Gorelov·Markus Holzmann·David M. Ceperley·Carlo Pierleoni
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Abstract

We study the gap closure with pressure of crystalline molecular hydrogen. The gaps are obtained from grand-canonical Quantum Monte Carlo methods properly extended to quantum and thermal crystals, simulated by Coupled Electron Ion Monte Carlo. Nuclear zero point effects cause a large reduction in the gap ($\sim 2eV$). \CP{Depending on the structure,} the fundamental indirect gap closes \CP{between 380GPa and} 530GPa for ideal crystals and 330-380GPa for quantum crystals. Beyond this pressure the system enters into a bad metal phase where the density of states at the Fermi level increases with pressure up to $\sim$450\CP{-500} GPa when the direct gap closes. Our work partially supports the interpretation of recent experiments in high pressure hydrogen.

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Vitaly Gorelov, Markus Holzmann, David M. Ceperley, Carlo Pierleoni. 2020-02-15. Energy gap closure of crystalline molecular hydrogen with pressure. https://doi.org/10.1103/physrevlett.124.116401

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