We explore the phase diagram, structures, electron properties, and potential superconductivity of the K–P system at pressures of up to 200 GPa through unbiased structure searching techniques and first-principles calculations. Five stable chemical stoichiometries (K₄P, K₃P, K₂P, KP, and KP₂) have been theoretically predicted. In particular, P₂ units or P-chains are uncovered in K₂P, KP, and KP₂ compounds with the existence of covalent bonds by analyzing the electron localization functions. And the Bader analysis demonstrates that charges transfer from K atoms to P atoms. Electron–phonon calculations show that the T_c of metallic I4/mmm-KP₂ is 22.01 K at 5 GPa. The investigating of the K–P system is in favor of understanding the crystal structures and corresponding properties of potassium phosphides, which also give a strong motivation to search and design new superconductor materials in other phosphides.

中文翻译：

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压力下K-P化合物的稳定性和超导性

通过无偏结构搜索技术和第一性原理计算，我们探索了在压力高达200 GPa时K-P系统的相图，结构，电子性质和潜在的超导性。从理论上预测了五个稳定的化学计量比（K ₄ P，K ₃ P，K ₂ P，KP和KP ₂）。特别地，通过分析电子定位功能，在具有共价键的K ₂ P，KP和KP ₂化合物中未发现P ₂单元或P链。Bader分析表明电荷从K原子转移到P原子。电子-声子计算表明，T _c在5 GPa时，金属I 4 / mmm -KP _2的最大强度为22.01 K. 对K-P体系的研究有利于理解磷化钾的晶体结构和相应的特性，这也为寻找和设计其他磷化物中的新超导体材料提供了强大的动力。