High-pressure structures of yttrium hydrides. (14th July 2017)

• Record Type: Journal Article
• Authors: Liu, Lu-Lu; Sun, Hui-Juan; Wang, C Z; Lu, Wen-Cai
• Is Part Of: Journal of physics. Volume 29:Number 32(2017)
• Publication Date: 2017-07-14
• Subjects: high pressure structure -- superconductivity -- yttrium hydrides; Condensed matter -- Periodicals; Matière condensée -- Périodiques; Vaste stoffen; Vloeistoffen; Natuurkunde; Electronic journals; Computer network resources; 530.4105
• DOI: 10.1088/1361-648X/aa787d
• Languages: English
• ISSNs: 0953-8984

Abstract

Abstract: 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.