The theoretical predictions and experimental synthesis of H3S and LaH10 superconductors with record high superconducting transition tempera-tures(Tc)have promoted the hydrogen-based superconducors to be a research hotspot in the field of solid-state physics.Here,we predict an unprecedented layered structure CaHi5,with high Te of 189 K at 200 GPa using ab initio calculations.As concerns the novel structure,one layer is made of a hydrogen nonagon,the other layer consists of a Ca atom and six H2 molecular units surrounding the Ca atom.This layered structure was also found in SrH155,YH15,and LaH15 at high pressures,each materials exhibit high Tc especially YH15 can reach above 200 K at 220 GPa.It repre-sents the second class of layered superhydrides with high value of Tc after pentagraphene like HfH10.

Yue Chen;Zhengtao Liu;Ziyue Lin;Qiwen Jiang;Mingyang Du;Zihan Zhang;Hao Song;Hui Xie;Tian Cui;Defang Duan

State Key Laboratory of Superhard Materials,College of Physics,Jilin University,Changchun 130012,China;Institute of High Pressure Physics,School of Physical Science and Technology,Ningbo University,Ningbo 315211,China

物理学前沿

[1]Yue Chen;Zhengtao Liu;Ziyue Lin;Qiwen Jiang;Mingyang Du;Zihan Zhang;Hao Song;Hui Xie;Tian Cui;Defang Duan-.High Tc superconductivity in layered hydrides XH15(X=Ca,Sr,Y,La)under high pressures)[J].物理学前沿,2022(06):103-109

XH15,superconducors,CaHi5,nonagon,SrH155,YH15,LaH15,superhydrides,pentagraphene,HfH10

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