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High-pressure structures of yttrium hydrides

TitleHigh-pressure structures of yttrium hydrides
Publication TypeJournal Article
Year of Publication2017
AuthorsLiu, LL, Sun, HJ, Wang, CZ, Lu, WC
JournalJournal of Physics-Condensed Matter
Date Published08
Type of ArticleArticle
ISBN Number0953-8984
Accession NumberWOS:000405568300001
Keywordsab-initio, algorithm, augmented-wave method, basis-set, genetic, high pressure structure, hydrogen, metals, optimization, physics, superconductivity, total-energy calculations, yh3, yttrium hydrides

In this work, the crystal structures of YH3 and YH4 at high pressure (100-250 GPa) have been explored using a genetic algorithm combined with first-principles calculations. New structures of YH3 with space group symmetries of P21/m and I4/mmm were predicted. The electronic structures and the phonon dispersion properties of various YH3 and YH4 structures at different temperatures and pressures were investigated. Among YH3 phases, the P21/m structure of YH3 was found to have a relatively high superconducting transformation temperature T-c of 19 K at 120 GPa, which is reduced to 9 K at 200 GPa. Other YH3 structures have much lower T(c)s. Compared with YH3, the T-c of the YH4 compound is much higher, i.e. 94 K at 120 GPa and 55 K at 200 GPa.

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Exploratory Theory