评估掺杂钙钛矿氢化物 KMgH$_3$ 的可能超导性：晶格非谐性与自旋涨落效应
Assessing the possible superconductivity in doped perovskite hydride KMgH$_3$: Effects of lattice anharmonicity and spin fluctuations
AI总结：
本文基于第一性原理和SCDFT研究了空穴掺杂钙钛矿氢化物KMgH$_3$的超导性，发现晶格非谐性在稳定区增强转变温度，而显著的自旋涨落效应会抑制超导配对并降低$T_{\mathrm{c}}$。
AI中文摘要：
本文基于第一性原理研究了不同掺杂浓度和对应不同压力的晶格参数下，均匀空穴掺杂钙钛矿氢化物 KMgH$_3$ 的超导特性。利用超导体密度泛函理论（SCDFT）预测了超导转变温度（$T_{\mathrm{c}}$），并考虑和检验了晶格非谐性与自旋涨落效应。尽管晶格非谐性倾向于在动力学稳定性边缘抑制超导性，但在非谐效应使相稳定的区域，$T_{\mathrm{c}}$ 得到增强。在空穴掺杂的 \ce{KMgH3} 中发现了显著的自旋涨落（SF）效应，该效应抵消了声子介导的配对并降低了 $T_{\mathrm{c}}$。本文还评估了类似氢化物中这种反常强 SF 效应（其氢的 1-$s$ 能带在费米能级处孤立存在），并探讨了其与电子态密度的相关性。
英文摘要：
The superconducting properties of uniformly hole-doped perovskite hydride KMgH$_3$ with varying doping concentration and lattice parameter corresponding to different pressures were investigated from first principles. The superconducting transition temperature ($T_{\mathrm{c}}$) was predicted from the density functional theory for superconductors (SCDFT), where the effects of lattice anharmonicity and spin-fluctuation were considered and examined. Although lattice anharmonicity tends to suppress superconductivity around the edge of dynamical stability, where the phase is stabilized due to anharmonic effects, $T_{\mathrm{c}}$ is enhanced. In the hole-doped \ce{KMgH3}, substantial spin-fluctuation (SF) effects were discovered, which counters the phonon-mediated pairing and decreases $T_{\mathrm{c}}$. Such anomalously strong SF is evaluated for similar hydrides, where the hydrogen 1-$s$ bands are isolated at the Fermi level, and its correlation with the electronics density of states was explored.
