KFe₂As₂ is one of the representatives of iron-based superconductors. Many interesting features distinguish this compound from other iron-based superconductors, e.g., a realization of the Pauli limit or an occurrence of the superconducting gap with nodal lines. Moreover, with increasing pressure, the isostructural phase transition from the tetragonal to collapsed tetragonal phase is experimentally observed. We discuss the structural, electronic, and superconducting properties of the KFe₂As₂ under pressure using the ab initio density functional theory (DFT) methods. We analyze the untypical properties of this superconductor considering, among others, the Fermi surfaces or the dependence of the anion height from the iron layer on the superconducting critical temperature.

中文翻译：

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KFe 2 As 2在压力下的超导性：四方相和塌陷四方相的从头算研究

KFe ₂ As ₂是铁基超导体的代表之一。许多有趣的特征使该化合物与其他铁基超导体区别开来，例如实现保利极限或出现带有节线的超导间隙。此外，随着压力的增加，实验观察到从四方相到塌陷的四方相的同构相转变。我们讨论KFe ₂ As ₂的结构，电子和超导特性在压力下使用从头算密度函数理论（DFT）方法。我们分析了这种超导体的非典型特性，其中包括费米表面或铁层阴离子高度与超导临界温度之间的关系。