Superconducting thorium hydrides under high pressure

There are lots of efforts on the investigate for high-temperature superconductors in hydrogen-rich system, since the LaH10 (250-260 K) and SH3 (203 K) compounds smashed the record for superconducting temperatures above 200 K. In this study, as a result of extensive simulations, we propose several unreported thorium hydrides under pressures, using our in-house developed CALYPSO structure searching method in combination with density functional theory. New ThH3 and Th2H7 structures are found as thermodynamically stable phases at atmospheric pressure. As a result of the analysis of the electronic properties in those predicted structures, it is found that the f electrons of Th and the s electrons of H mainly contribute to the fermi level, thus leading to the superconductivity. Our results enrich the knowledge in the Th-H system and provide insights into designing superconducting hydrides under high pressure.