Electrides as a unique class of emerging materials exhibit fascinating properties and hold important significance for understanding matter under extreme conditions, which is characterized by valence electrons localized into the interstitial space as quasi-atoms (ISQs). In this work, using crystal structure prediction and first-principles calculations, we identified seven stable phases of Mg–Li that are electrides with novel electronic properties under high pressures. Among them, MgLi₁₀ is a semiconductor with a band gap of 0.22 eV, and Pm-3m MgLi is a superconductor with a superconducting transition temperature of 22.8 K. The important role played by the localization degree of ISQs in the superconducting transition temperature of these electrides is revealed by systematic comparison of Mg–Li with other Li-rich electride superconductors. Furthermore, we proved that Pm-3m MgLi and Pnma MgLi also have distinct topological behavior with metallic surface states and the nonzero Z₂ invariant. The simultaneous coexistence of superconductivity, electronic band topology, and electride property in the same structure of Pm-3m MgLi and Pnma MgLi demonstrates the feasibility of realizing multiquantum phases in a single material, which will stimulate further research in these interdisciplinary fields.

中文翻译：

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Mg-Li 电泳物在高压下同时具有超导和拓扑特性


电泳物作为一类独特的新兴材料，表现出迷人的特性，对于理解极端条件下的物质具有重要意义，其特征是价电子以准原子 （ISQ） 的形式定位在间隙空间中。在这项工作中，使用晶体结构预测和第一性原理计算，我们确定了 Mg-Li 的 7 个稳定相，它们是在高压下具有新颖电子特性的电泳物。其中，MgLi₁₀ 是带隙为 0.22 eV 的半导体，Pm-3 m MgLi 是超导转变温度为 22.8 K 的超导体。通过将 Mg-Li 与其他富锂电泳超导体的系统比较，揭示了 ISQ 的定位度在这些电泳物的超导转变温度下发挥的重要作用。此外，我们证明了 Pm-3 m MgLi 和 Pnma MgLi 也具有独特的拓扑行为，具有金属表面状态和非零 Z₂ 不变性。Pm-3 m MgLi 和 Pnma MgLi 的同一结构中超导性、电子能带拓扑和电泳特性同时共存，证明了在单一材料中实现多量子相的可行性，这将激发这些跨学科领域的进一步研究。