Inorganic electrides have gained remarkable attention for their intrinsic physical properties derived from loosely bound anionic electrons. Herein, using ab initio evolutionary structure search, we found that the formulation of Ca and Si with the stoichiometric ratio of 3:1 can be stabilized under mildly external pressure, where the hexagonal P6₃/mmc phase is the most stable structure under a wide pressure range from 13.5 to 104 GPa. Based on the analysis of the electrostatic difference potential as an identifier of electrides, together with the electronic structure and electron localization function results, we have identified the P6₃/mmc Ca₃Si as the one-dimensional (1D) electride, whose chemical formula could be expressed as [Ca₃Si]²⁺:2e^–. Interestingly, the electron mobility and the electron–phonon interaction strength of P6₃/mmc Ca₃Si electride present the strong electronic anisotropy, illustrating the 1D electron confinement nature. Moreover, due to the strong electron–phonon coupling between interstitial electrons and phonons from Ca atoms, the P6₃/mmc Ca₃Si exhibits superconductivity with a predicted superconducting transition temperature T_c of about 17.6 K at 100 GPa, which is the highest among the already known 1D electrides. Our works provide new insight into new thermodynamically stable related alkaline earth based electrides and their potential for high performance in electronics and catalytic applications.

中文翻译：

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一维电极Ca ₃ Si中的电子各向异性和超导性

无机驻极体因其松散结合的阴离子电子的内在物理性​​质而引起了人们的极大关注。在这里，使用从头开始的演化结构搜索，我们发现，化学计量比为3：1的Ca和Si的配方可以在适度的外压下稳定，其中六方P 6 ₃ / mmc相是在室温下最稳定的结构。压力范围从13.5至104 GPa。通过对作为电子标识符的静电势电势的分析，电子结构和电子定位功能结果，我们确定了P 6 ₃ / mmc Ca ₃Si是一维（一维）电子，其化学式可以表示为[Ca ₃ Si] ²⁺：2e ^–。有趣的是，P 6 ₃ / mmc Ca ₃ Si氮化物的电子迁移率和电子-声子相互作用强度表现出很强的电子各向异性，说明了1D电子约束性质。此外，由于间隙电子与来自Ca原子的声子之间的强电子-声子耦合，P 6 ₃ / mmc Ca ₃ Si表现出超导性，并具有预测的超导转变温度T _c在100 GPa时约为17.6 K，这是已知的一维电子中最高的。我们的工作为新的热力学稳定的相关碱土金属电极及其在电子和催化应用中的高性能潜力提供了新的见解。