标题： 电子-声子耦合对金属中热输运的影响：求解耦合电子-声子玻尔兹曼输运方程的蒙特卡罗方法 显示英文标题

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

摘要： 在本工作中，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。 在此方法中，从第一性原理计算了各向异性电子能带结构、整个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。 使用此方法，在{\alpha }-U 和 Ag 中进行了不同温度下的耦合 e-ph 热输运蒙特卡罗模拟。 这两种材料被选为展示该方法在不同领域适用性的例子。 结果表明，由于声子散射引起的电子弛豫时间比由于电子散射引起的声子弛豫时间小几个数量级。 结果还表明，在声子热输运中，ph-e 散射的影响几乎可以忽略不计，ph-ph 散射主导声子输运。 在高温下，电子在{\alpha }-U 和 Ag 中主导热输运。 然而，在低温下，{\alpha }-U 的总热导率中声子贡献是显著的。 此外，在低到中等温度下，洛伦兹比偏离了 Sommerfeld 值，此时魏德曼-弗朗茨定律不适用。 最后，我们展示了 Ag 的电子热导率比其声子热导率表现出更强的尺寸效应。 显示英文摘要

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 {\alpha}-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 {\alpha}-U and Ag. However, at low temperature, the phonon contribution to the total thermal conductivity of {\alpha}-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.