Due to their unique structure properties, most of the electrides that possess extra electrons locating in interstitial regions as anions are insulators. Metallic and superconducting electrides are very rare under ambient conditions. We systematically search possible compounds in Ca–S systems stabilized under various pressures up to 200 GPa, and investigate their crystal structures and properties using first-principles calculations. We predict a series of novel stoichiometries in Ca–S systems as potential superconductors, including P2₁/m Ca₃S, P4mbm Ca₃S, Pnma Ca₂S, Cmcm Ca₂S, Fddd CaS₂, Immm CaS₃ and C2/c CaS₄. The P4mbm Ca₃S phase exhibits a maximum T _c value of ∼20 K. It is interesting to notice that the P2₁/m Ca₃S and Pnma Ca₂S stabilized at 60 and 50 GPa behave as superconducting electrides with critical temperatures T _c of 7.04 K and 0.26 K, respectively. More importantly, our results demonstrate that P2₁/m Ca₃S and Pnma Ca₂S are dynamically stable at 5 GPa and 0 GPa, respectively, indicating a high possibility to be quenched to ambient condition or synthesized using the large volume press.

由于其独特的结构特性，大多数具有位于间隙区域作为阴离子的额外电子的电子化物是绝缘体。金属和超导电子化物在环境条件下非常罕见。我们系统地搜索在高达 200 GPa 的各种压力下稳定的 Ca-S 系统中可能的化合物，并使用第一性原理计算研究它们的晶体结构和性质。我们预测 Ca-S 系统中的一系列新化学计量作为潜在的超导体，包括P 2 ₁ / m Ca ₃ S、P 4mbm Ca ₃ S、Pnma Ca ₂ S、Cmcm Ca ₂ S、FdddCaS ₂ , Immm CaS ₃和C 2 / c CaS ₄。P 4 mbm Ca ₃ S 相的最大T c _值约为 20 K。有趣的是，稳定在 60 和 50 GPa 的P 2 ₁ / m Ca ₃ S 和Pnma Ca ₂ S 表现为超导电子体，具有临界温度T _c分别为 7.04 K 和 0.26 K。更重要的是，我们的结果表明P 2 ₁/ m Ca ₃ S 和Pnma Ca ₂ S 分别在 5 GPa 和 0 GPa 下动态稳定，表明很有可能被淬火到环境条件或使用大体积压力机合成。