Polyhydride CeH9 with an atomic-like hydrogen clathrate structure

• Published in: Nature communications Vol. 10; no. 1; pp. 1 - 7
• Main Authors: Li, Xin, Huang, Xiaoli, Duan, Defang, Pickard, Chris J., Zhou, Di, Xie, Hui, Zhuang, Quan, Huang, Yanping, Zhou, Qiang, Liu, Bingbing, Cui, Tian
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.08.2019; Nature Publishing Group; Nature Portfolio
• Subjects: 119/118; 639/638/263/915; 639/638/440/94; Cages; Cerium; Clathrates; Compression; High temperature superconductors; Humanities and Social Sciences; Hydrides; Hydrogen; Hydrogen storage; Lanthanum; Localization; Metallic hydrogen; multidisciplinary; Science; Science (multidisciplinary)
• DOI: 10.1038/s41467-019-11330-6
• ISSN: 2041-1723

Compression of hydrogen-rich hydrides has been proposed as an alternative way to attain the atomic metallic hydrogen state or high-temperature superconductors. However, it remains a challenge to get access to these states by synthesizing novel polyhydrides with unusually high hydrogen-to-metal ratios. Here we synthesize a series of cerium (Ce) polyhydrides by a direct reaction of Ce and H 2 at high pressures. We discover that cerium polyhydride CeH 9 , formed above 100 GPa, presents a three-dimensional hydrogen network composed of clathrate H 29 cages. The electron localization function together with band structure calculations elucidate the weak electron localization between H-H atoms and confirm its metallic character. By means of Ce atom doping, metallic hydrogen structure can be realized via the existence of CeH 9 . Particularly, Ce atoms play a positive role to stabilize the sublattice of hydrogen cages similar to the recently discovered near-room-temperature lanthanum hydride superconductors. Obtainment of hydrogen-rich metal hydrides that are high-temperature superconductors has been demonstrated under very high pressure, but is still largely unexplored. Here the authors synthesize CeH 9 , with a structure related to solid metallic hydrogen, at relatively low pressure and without need for heating.