title: Pressure-induced superconductivity in H2-containing hydride PbH4(H2)2.
abstract: High pressure structure, stability, metallization, and superconductivity of PbH4(H2)2, a H2-containing compound combining one of the heaviest elements with the lightest element, are investigated by the first-principles calculations. The metallic character is found over the whole studied pressure range, although PbH4(H2)2 is metastable and easily decompose at low pressure. The decomposition pressure point of 133 GPa is predicted above which PbH4(H2)2 is stable both thermodynamically and dynamically with the C2/m symmetry. Interestedly, all hydrogen atoms pairwise couple into H2 quasi-molecules and remain this style up to 400 GPa in the C2/m structure. At high-pressure, PbH4(H2)2 tends to form the Pb-H2 alloy. The superconductivity of Tc firstly rising and then falling is observed in the C2/m PbH4(H2)2. The maximum of Tc is about 107 K at 230 GPa. The softening of intermediate-frequency phonon induced by more inserted H2 molecules is the main origin of the high Tc. The results obtained represent a significant step toward the understanding of the high pressure behavior of metallic hydrogen and hydrogen-rich materials, which is helpful for obtaining the higher Tc.
authors.affiliation: Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences and The Chinese University of Hong Kong, Shenzhen, 518055, China.
authors.forename: Ya
authors.initials: Y
authors.lastname: Cheng
authors.affiliation: Department of Physics, Yantai University, Yantai, 264005, China.
authors.forename: Chao
authors.initials: C
authors.lastname: Zhang
authors.affiliation: Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences and The Chinese University of Hong Kong, Shenzhen, 518055, China.
authors.forename: Tingting
authors.initials: T
authors.lastname: Wang
authors.affiliation: Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences and The Chinese University of Hong Kong, Shenzhen, 518055, China.
authors.forename: Guohua
authors.initials: G
authors.lastname: Zhong
authors.affiliation: Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences and The Chinese University of Hong Kong, Shenzhen, 518055, China.
authors.forename: Chunlei
authors.initials: C
authors.lastname: Yang
authors.affiliation: Center for High Pressure Science and Technology Advanced Research, Shanghai 201203, China.
authors.forename: Xiao-Jia
authors.initials: XJ
authors.lastname: Chen
authors.affiliation: Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences and The Chinese University of Hong Kong, Shenzhen, 518055, China.|Beijing Computational Science Research Center, Beijing 100089, China.
authors.forename: Hai-Qing
authors.initials: HQ
authors.lastname: Lin