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arXiv · 2411.09966

Assessing the possible superconductivity in doped perovskite hydride KMgH$_3$: Effects of lattice anharmonicity and spin fluctuations

Shaocong Lu·Ryosuke Akashi·Mitsuaki Kawamura·Shinji Tsuneyuki
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Abstract

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.

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Shaocong Lu, Ryosuke Akashi, Mitsuaki Kawamura, Shinji Tsuneyuki. 2024-11-15. Assessing the possible superconductivity in doped perovskite hydride KMgH$_3$: Effects of lattice anharmonicity and spin fluctuations. https://arxiv.org/abs/2411.09966

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