Design of superconducting compounds at lower pressure via intercalating XH 4 molecules (X = B, C, and N) into fcc lattices

• Published in: Chinese physics B 2024-11, Vol.33 (12), p.127101
• Main Authors: Zhao 赵, Yue 玥, Liu 刘, Sihan 思涵, Liu 刘, Jiao 骄, Gu 顾, Tingting 婷婷, Hao 郝, Jian 健, Shi 石, Jingming 景明, Cui 崔, Wenwen 文文, Li 李, Yinwei 印威
• Format: Article
• Language: English
• ISSN: 1674-1056; 2058-3834
• DOI: 10.1088/1674-1056/ad7c31

Recently, many encouraging experimental advances have been achieved in ternary hydrides superconductors under high pressure. However, the extreme pressure required is indeed a challenge for practical application, which promotes a further exploration for high temperature ( T c ) superconductors at relatively low pressure. Herein, we performed a systematic theoretical investigation on a series of ternary hydrides with stoichiometry AX 2 H 8 , which is constructed by interacting molecular X H 4 ( X = B, C, and N) into the fcc metal A lattice under low pressure of 0–150 GPa. We uncovered five compounds which are dynamically stable below 100 GPa, e.g., AcB 2 H 8 (25 GPa), LaB 2 H 8 (40 GPa), RbC 2 H 8 (40 GPa), CsC 2 H 8 (60 GPa), and SrC 2 H 8 (65 GPa). Among them, AcB 2 H 8 , which is energetically stable above 2.5 GPa, exhibits the highest T c of 32 K at 25 GPa. The superconductivity originates mainly from the coupling between the electron of Ac atoms and the associated low-frequency phonons, distinct from the previous typical hydrides with H-derived superconductivity. Our results shed light on the future exploration of superconductivity among ternary compounds at low pressure.