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Electronic excitations and metallization of dense solid hydrogen

Authors :
Ronald E. Cohen
Ivan Naumov
Russell J. Hemley
Source :
Proceedings of the National Academy of Sciences. 110:13757-13762
Publication Year :
2013
Publisher :
Proceedings of the National Academy of Sciences, 2013.

Abstract

Theoretical calculations and an assessment of recent experimental results for dense solid hydrogen lead to a unique scenario for the metallization of hydrogen under pressure. The existence of layered structures based on graphene sheets gives rise to an electronic structure related to unique features found in graphene that are well studied in the carbon phase. The honeycombed layered structure for hydrogen at high density, first predicted in molecular calculations, produces a complex optical response. The metallization of hydrogen is very different from that originally proposed via a phase transition to a close-packed monoatomic structure, and different from simple metallization recently used to interpret recent experimental data. These different mechanisms for metallization have very different experimental signatures. We show that the shift of the main visible absorption edge does not constrain the point of band gap closure, in contrast with recent claims. This conclusion is confirmed by measured optical spectra, including spectra obtained to low photon energies in the infrared region for phases III and IV of hydrogen.

Details

ISSN :
10916490 and 00278424
Volume :
110
Database :
OpenAIRE
Journal :
Proceedings of the National Academy of Sciences
Accession number :
edsair.doi.dedup.....79e33a6f2600bd4011d9cec47966da6c
Full Text :
https://doi.org/10.1073/pnas.1312256110