Recent discoveries of alkali metal structures with novel properties at high pressures have stimulated considerable interest in binary mixtures of these metals under compression. This work reports a broad investigation of the physical and chemical behaviors of different Na–K stoichiometries by first-principles calculations and swarm-intelligence structure searching methodology. In addition to five structures previously proposed, seven new structures with stoichiometries of NaK, NaK₂, and NaK₃ were uncovered. New NaK₂ compounds with Pm and Pnma structures are potential superconductors with T_c of 12.17 K at 250 GPa and 6.26 K at 400 GPa, respectively. The NaK and NaK₃ compounds show intriguing decomposition–recombination behavior. The newly found Cmcm structure of NaK, Pm structure of NaK₂, and Pmmm and Cmcm structures of NaK₃ are electrides with strong interstitial electron localization. What's more, interesting reversible charge transfer between Na and K occurred as the pressure increased. Our discoveries prove that pressure is a powerful tool for creating new exotic materials in the binary alkali compounds.

最近在高压下具有新性质的碱金属结构的发现激发了对这些金属在压缩下的二元混合物的极大兴趣。这项工作报告了通过第一性原理计算和群体智能结构搜索方法对不同 Na-K 化学计量的物理和化学行为的广泛研究。除了先前提出的五个结构之外，还发现了七个具有 NaK、NaK ₂和 NaK ₃化学计量的新结构。具有Pm和Pnma结构的新型 NaK ₂化合物是潜在的超导体，其T _c在 250 GPa 下分别为 12.17 K 和 6.26 K 在 400 GPa 下。NaK 和 NaK_{3 种}化合物显示出有趣的分解-重组行为。新发现的CMCM NAK时，的结构PM的NaK的结构₂，和PMMM和CMCM的NaK的结构₃是具有很强的间质性电子局域电子晶体。更重要的是，随着压力的增加，Na 和 K 之间发生了有趣的可逆电荷转移。我们的发现证明压力是在二元碱性化合物中创造新奇特材料的有力工具。