Ternary superconducting hydrides stabilized via Th and Ce elements at mild pressures

• Published in: Fundamental research (Beijing) Vol. 4; no. 3; pp. 550 - 556
• Main Authors: Jiang, Qiwen, Zhang, Zihan, Song, Hao, Ma, Yanbin, Sun, Yuanhui, Miao, Maosheng, Cui, Tian, Duan, Defang
• Format: Journal Article
• Language: English
• Published: China Elsevier B.V 01.05.2024; KeAi Publishing; KeAi Communications Co. Ltd
• Subjects: Ab initio calculations; Electron-phonon coupling; High pressure; Hydrides; Superconductivity; Hydrides; Ab initio calculations; Electron-phonon coupling; Superconductivity; High pressure
• ISSN: 2667-3258; 2096-9457; 2667-3258
• DOI: 10.1016/j.fmre.2022.11.010

The discovery of covalent H3S and clathrate structure LaH10 with excellent superconducting critical temperatures at high pressures has facilitated a multitude of research on compressed hydrides. However, their superconducting pressures are too high (generally above 150 GPa), thereby hindering their application. In addition, making room-temperature superconductivity close to ambient pressure in hydrogen-based superconductors is challenging. In this work, we calculated the chemically “pre-compressed” Be-H by heavy metals Th and Ce to stabilize the superconducting phase near ambient pressure. An unprecedented ThBeH8 (CeBeH8) with a “fluorite-type” structure was predicted to be thermodynamically stable above 69 GPa (76 GPa), yielding a Tc of 113 K (28 K) decompressed to 7 GPa (13 GPa) by solving the anisotropic Migdal–Eliashberg equations. Be-H vibrations play a vital role in electron–phonon coupling and structural stability of these ternary hydrides. Our results will guide further experiments toward synthesizing ternary hydride superconductors at mild pressures. [Display omitted]