Experimental discovery of near-room-temperature (NRT) superconductivity in highly-compressed H$_3$S, LaH$_1$$_0$ and YH$_6$ restores fundamental interest to electron-phonon pairing mechanism in superconductors. One of prerequisites of phonon-mediated NRT superconductivity in highly-compressed hydrides is strong electron-phonon interaction, which can be quantified by dimensionless ratios of Bardeen-Cooper-Schrieffer (BCS) theory vs $k{_B}T{_c}$/(${\hslash}$${\omega}{_l}{_n}$), where Tc is the critical temperature and ${\omega}{_l}{_n}$ is the logarithmic phonon frequency (Mitrovic et al. 1984 Phys. Rev. B 29 184). However, all known strong-coupling correction functions for BCS ratios are applicable for $k{_B}T{_c}$/(${\hslash}$${\omega}{_l}{_n}$)<0.20, which is not high enough $k{_B}T{_c}$/(${\hslash}$${\omega}{_l}{_n}$) range for NRT superconductors, because the latter exhibit variable values of 0.13 < $k{_B}T{_c}$/(${\hslash}$${\omega}{_l}{_n}$) < 0.32. In this paper, we reanalyze full experimental dataset (including data for highly-compressed H3S) and find that strong-coupling correction functions for the gap-to-critical-temperature ratio and for the specific-heat-jump ratio are double-valued nearly-linear functions of $k{_B}T{_c}$/(${\hslash}$${\omega}{_l}{_n}$).

中文翻译：

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对 Bardeen-Cooper-Schrieffer 比率的双值强耦合修正

在高度压缩的 H$_3$S、LaH$_1$$_0$ 和 YH$_6$ 中近室温 (NRT) 超导性的实验发现恢复了对超导体中电子-声子配对机制的基本兴趣。高压缩氢化物中声子介导的 NRT 超导性的先决条件之一是强电子 - 声子相互作用，这可以通过 Bardeen-Cooper-Schrieffer (BCS) 理论与 $k{_B}T{_c}$/ 的无量纲比来量化(${\hslash}$${\omega}{_l}{_n}$)，其中 Tc 是临界温度，${\omega}{_l}{_n}$ 是对数声子频率（Mitrovic et al. 1984 年物理修订版 B 29 184）。然而，所有已知的 BCS 比率强耦合校正函数都适用于 $k{_B}T{_c}$/(${\hslash}$${\omega}{_l}{_n}$)<0.20，这对于 NRT 超导体来说还不够高 $k{_B}T{_c}$/(${\hslash}$${\omega}{_l}{_n}$) 范围，因为后者表现出 0.13 < $k{_B}T{_c}$/(${\hslash}$${\omega}{_l}{_n}$) < 0.32。在本文中，我们重新分析了完整的实验数据集（包括高压缩 H3S 的数据），发现间隙临界温度比和比热跃变比的强耦合校正函数几乎是双值的-$k{_B}T{_c}$/(${\hslash}$${\omega}{_l}{_n}$) 的线性函数。