We report the theoretical prediction of two high-performing hydride superconductors BaSiH₈ and SrSiH₈. They are thermodynamically stable above pressures of 130 and 174 GPa, respectively, and metastable below that. Employing anharmonic phonon calculations, we determine the minimum pressures of dynamical stability to be around 3 GPa for BaSiH₈ and 27 GPa for SrSiH₈, and using the fully anisotropic Migdal-Eliashberg theory, we predict T_c’s around 71 and 126 K, respectively. We also introduce a method to estimate the lowest pressure of synthesis, based on the calculation of the enthalpy barriers protecting the BaSiH₈ \(Fm\bar{3}m\) structure from decomposition at various pressures. This kinetic pressure threshold is sensibly higher than the one based on dynamic stability, but gives a much more rigorous limit for synthesizability.

我们报告了两种高性能氢化物超导体 BaSiH ₈和 SrSiH ₈的理论预测。它们在分别高于 130 和 174 GPa 的压力下是热力学稳定的，低于此压力是亚稳态的。采用非谐声子计算，我们确定动态稳定性的最小压力为 BaSiH 8 的 3 GPa 和 SrSiH _8的27 GPa ，并使用完全各向异性的 Migdal-Eliashberg 理论，我们预测T _c的值在 71 和 126 K 左右，分别。我们还介绍了一种估计合成最低压力的方法，该方法基于保护 BaSiH ₈ \(Fm\bar{3}m\)的焓势垒的计算。 在各种压力下分解的结构。这个动态压力阈值明显高于基于动态稳定性的阈值，但对可合成性给出了更严格的限制。