Phonon-mediated high-temperature superconductivity in clathrate superhydride ThCeH₁₈ under pressure

Predicting high-temperature superconductivity in hydrogen-rich dense metallic states under pressure remains a significant challenge. The discovery of new phases of metal hydrides is vital for advancing this area of research. In our study, we present the superconducting phases of ThCeH₁₈ using a search strategy based on potential energy surfaces and evolutionary algorithms under pressure. Consequently, ThCeH₁₈ is thermodynamically stable in a crystalline hexagonal unit cell with the space group [Formula: see text], similar to CeLaH₁₈ and LaThH₁₈. The critical importance of hydrogen atoms is demonstrated, showcasing their significant influence on the evolution of T_c. Isotropic superconductivity in ThCeH₁₈, driven by electron-phonon interactions and analyzed using the stochastic self-consistent harmonic approximation (SSCHA) to account for anharmonicity, reveals a strong anharmonic correction and strong electron-phonon coupling, resulting in high-temperature superconductivity with a T_c of approximately 136 K at 50 GPa.This approach provides a promising direction for identifying new classes of superconducting materials and offers valuable insights into enhancing superconductivity through structural prediction.