Metal-Element-Incorporation Induced Superconducting Hydrogen Clathrate Structure at High Pressure
Jiayu Ma1,2†, Junlin Kuang1†, Wenwen Cui1*, Ju Chen1, Kun Gao1, Jian Hao1*, Jingming Shi1, and Yinwei Li1
1Laboratory of Quantum Functional Materials Design and Application, School of Physics and Electronic Engineering, Jiangsu Normal University, Xuzhou 221116, China 2CW Chu College, Jiangsu Normal University, Xuzhou 221116, China
Abstract：The recent observation of high critical temperature $T_{\rm c}$ in lanthanum and Yttrium hydrides confirms the key role of hydrogen cage (H-cage) in determining high superconductivity. Here, we present a new class of metastable H$_{12}$ clathrate structures based on the icosahedral $cI24$-Na that can be stabilized by incorporation of metal elements. Analysis shows that the charge transfer from metal atoms to H atoms contributes to forming the H$_{12}$ clathrate. Nine dynamically stable structures are identified to exhibit superconductivity, and a maximum $T_{\rm c}$ of 28 K is found in voids-doped Mo$_{6}$H$_{24}$. Calculations reveal that the low $T_{\rm c}$ is attributed to the weak interaction between H atoms in each cage due to the long H–H distance. The current results provide a possible route to design H-cage containing superconductors.
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2021, Vol. 38 
