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arXiv 2402.08150cond-mat.mtrl-scinucl-th
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电子-声子耦合对金属中热输运的影响:一种求解耦合电子-声子玻尔兹曼输运方程的蒙特卡罗方法

Effect of electron-phonon coupling on thermal transport in metals: a Monte Carlo approach for solving the coupled electron-phonon Boltzmann transport equations

Jie Peng, W. Ryan Deskins, Maria Helena Braga, Anter El-Azab

AI总结:

本研究基于第一性原理开发蒙特卡罗方法求解耦合电子-声子玻尔兹曼输运方程,探究金属热输运,发现高温下电子主导输运,低温下声子贡献显著且Wiedemann-Franz定律失效。

摘要:

在这项工作中,通过第一性原理计算研究了电子-声子(e-ph)耦合对金属中电子和声子输运的影响。开发了一种蒙特卡罗(MC)方法来求解耦合的电子-声子玻尔兹曼输运方程,以研究金属的热导率。在该方法中,各向异性的电子能带结构、全布里渊区内的声子色散,以及电子和声子的模式依赖热弛豫时间均通过第一性原理计算得出。利用该方法,对α-U和Ag在不同温度下的耦合e-ph热输运进行了MC模拟。选择这两种材料是为了证明该方法在不同领域的适用性。结果表明,由声子散射导致的电子弛豫时间比由电子散射导致的声子弛豫时间小几个数量级。结果还显示,在声子热输运中,ph-e散射的影响几乎可以忽略不计,ph-ph散射主导了声子输运。在高温下,电子主导了α-U和Ag中的热输运。然而,在低温下,声子对α-U总热导率的贡献是显著的。此外,Lorenz比在低至中等温度下偏离了Sommerfeld值,此时Wiedemann-Franz定律不再适用。最后,我们表明Ag的电子热导率比其声子热导率表现出更强的尺寸效应。

英文摘要:

In this work, the effect of electron-phonon (e-ph) coupling on both electron and phonon transport of metals is investigated via first principles calculations. A Monte-Carlo (MC) approach for solving the coupled electron-phonon Boltzmann transport equations is developed to investigate thermal conductivity of metals. In this approach, the anisotropic electron band structure, phonon dispersion in the full Brillouin zone, and mode-dependent thermal relaxation time of electrons and phonons are calculated from first principles. Using this approach, MC simulations of coupled e-ph thermal transport at different temperatures in α-U and Ag are performed. These two materials were selected as a way to demonstrate the applicability of the method in different fields. The results indicate that the electron relaxation time due to phonon scattering is orders of magnitude smaller than the phonon relaxation time due to electron scattering. The results also show that, in phonon thermal transport, the impact of ph-e scattering is almost negligible and the ph-ph scattering dominates phonon transport. At high temperature, the electrons dominate thermal transport in both α-U and Ag. However, at low temperature, the phonon contribution to the total thermal conductivity of α-U is significant. Moreover, the Lorenz ratio deviates from the Sommerfeld value at low to intermediate temperatures, where the Wiedemann-Franz law is not applicable. Finally, we show that the Ag electronic thermal conductivity shows a stronger size effect than its phonon thermal conductivity.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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