超导电性
铅(地质)
材料科学
相(物质)
高压
凝聚态物理
理论(学习稳定性)
热力学
物理
计算机科学
量子力学
地貌学
机器学习
地质学
作者
Bole Chen,Lewis J. Conway,Weiguo Sun,Xiao-Yu Kuang,Cheng Lu,Andreas Hermann
出处
期刊:Physical review
日期:2021-01-19
卷期号:103 (3)
被引量:46
标识
DOI:10.1103/physrevb.103.035131
摘要
Density functional theory calculations and crystal structure predictions using the particle swarm optimization method have been combined to determine stable hydrides of lead under pressure. In contrast to other group-IVa hydrides, the stoichiometry ${\mathrm{PbH}}_{6}$ is the first hydride to become stable, at just under 1 Mbar. For two previously studied stoichiometries, ${\mathrm{PbH}}_{4}$ and ${\mathrm{PbH}}_{8}$, energetically more favorable phases were identified to become stable around 2 Mbar. In all structures, the hydrogenic sublattices comprise negatively charged ${{\mathrm{H}}_{2}}^{\ensuremath{\delta}\ensuremath{-}}$ molecules. Competitive ${\mathrm{PbH}}_{4}$ and ${\mathrm{PbH}}_{6}$ structures are layered. ${\mathrm{PbH}}_{6}$ features ${\mathrm{H}}_{2}$ molecules intercalated between hcp Pb layers, the stable phase of dense pure lead, thus offering a potentially straightforward route towards synthesis. In ${\mathrm{PbH}}_{8}$, the Pb lattice adapts a $\ensuremath{\beta}$-Sn structure, and hydrogen atoms form quasi-one-dimensional-chains. All structures were found to be metallic and to feature superconductivity in their respective stability range, with moderately high ${T}_{c}$ in the range 60--100 K for ${\mathrm{PbH}}_{4}$ and ${\mathrm{PbH}}_{6}$ and 161--178 K for ${\mathrm{PbH}}_{8}$.
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