论文标题
高级麦克米兰方程及其用于分析高度压缩超导体的应用
Advanced McMillan's equation and its application for the analysis of highly-compressed superconductors
论文作者
论文摘要
电子 - 音波介导的超导性的理论要求了解完整的声子频谱以计算超导过渡温度，t $ _c $。但是，没有实验技术可以测量迄今为止高度压缩的近室温度（NRT）超导体中的声子频谱。 In this paper we propose to advance McMillan's approach (1968 Phys Rev 167 331) which utilizes the Debye temperature, T$_θ$ (an integrated parameter of full phonon spectrum), that we deduced by the fit of experimentally measured temperature-dependent resistance data, R(T), to Bloch-Gruneisen equation for highly-compressed black phosphorous, boron, GeAs, SiH$_4$, h $ _x $ s，d $ _y $ s，lah $ _x $和lad $ _y $。通过利用T $ _C $，DEBYE温度和电子偶联强度常数之间的关系，$λ_{e-Ph} $可以在给定超导体中确认/反驳电子 - Phonon机制。我们表明，用于高度压缩的黑色磷，硼，Geas，Sih $ _4 $的计算$λ_{e-ph} $，对于一个lah $ _ {10} $的样本与$λ_{e-ph} $ quats of LAH $ _ {10} $相当一致。还发现，在不同的老化阶段，Debye温度在H $ _3 $ s中的出色恒定。我们还表明，如果两个同位素对应物具有相似的形状，那么在电子音波现象学中，这些材料应服从t $ _ {c，1} $/t $ _ {c，2} $ = t $ = t $ = t $ _ {θ，1}，1}，1} $/t $ _ {ful）的关系。我们报告说，这些h $ _3 $ s-d $ _3 $ _3 $ s预测的比率与实验得出的比率大不相同。这暗示了H3S-D3S系统中的NRT超导性起源于一种以上的机制，在该机制中，电子 - phonon耦合将h $ _3 $ s vs n $ _3 $ s vs d $ _3 $ s提升，但在H $ _3 $ _3 $ _3 $ s和D $ _3 $ _3 $中剩下的NRT背景的主要起源。
A theory of electron-phonon mediated superconductivity requires the knowledge of full phonon spectrum to calculate superconducting transition temperature, T$_c$. However, there is no experimental technique which can measure phonon spectrum in highly-compressed near-room-temperature (NRT) superconductors to date. In this paper we propose to advance McMillan's approach (1968 Phys Rev 167 331) which utilizes the Debye temperature, T$_θ$ (an integrated parameter of full phonon spectrum), that we deduced by the fit of experimentally measured temperature-dependent resistance data, R(T), to Bloch-Gruneisen equation for highly-compressed black phosphorous, boron, GeAs, SiH$_4$, H$_x$S, D$_y$S, LaH$_x$ and LaD$_y$. By utilizing relations between T$_c$, Debye temperature and electron-phonon coupling strength constant, $λ_{e-ph}$ it is possible to affirm/disprove the electron-phonon mechanism in given superconductors. We show that computed $λ_{e-ph}$ for highly-compressed black phosphorous, boron, GeAs, SiH$_4$ and for one sample of LaH$_{10}$ are in a good agreement with $λ_{e-ph}$ values deduced from experimental data. It is also found remarkable constancy of Debye temperature in H$_3$S at different ageing stages. We also show that if phonon spectra of two isotopic counterparts have similar shape then within electron-phonon phenomenology these materials should obey the relation of T$_{c,1}$/T$_{c,2}$=T$_{θ,1}$/T$_{θ,2}$ (where 1 and 2 designate isotopes). We report that these ratios for H$_3$S-D$_3$S predicted by electron-phonon phenomenology are largely different from ratios deduced from experiment. This alludes that NRT superconductivity in H3S-D3S system is originated from more than one mechanism, where the electron-phonon coupling lifts T$_c$ in H$_3$S vs D$_3$S, but primary origin for NRT background of in both H$_3$S and D$_3$S remains to be discovered.
