论文标题
非平衡对金属电子偶联常数的影响
Non-equilibrium effects on electron-phonon coupling constant in metals
论文作者
论文摘要
了解金属中电子和声子之间的能量交换对于微型和纳米制造和系统设计很重要。电子 - 音波（E-PH）耦合常数是描述这种交换强度，但是在微平衡效应显着的微平衡效应的微观和纳米级，其变异仍然不清楚。在这项工作中，通过将完整的散射项转换为耦合电子和声子Boltzmann传输方程中的松弛时间近似形式来提出E-PH耦合模型。因此，非平衡效应包括在E-PH耦合常数的计算中。通过对金属表面上飞秒泵探针实验的超快动力学进行建模来验证耦合模型，这与散射项的完整整体处理显示出一致的结果。由于不同的声子分支之间的时间非平衡和电子在密闭空间中电子的空间非平衡性之间的时间非平衡，E-PH耦合常数大大降低。目前的工作不仅将促进对E-PH耦合常数的基本理解，而且还将促进对微观和纳米级耦合电子和声子传输的理论描述。
Understanding of the energy exchange between electrons and phonons in metals is important for micro- and nano-manufacturing and system design. The electron-phonon (e-ph) coupling constant is to describe such exchange strength, yet its variation remains still unclear at micro- and nanoscale where the non-equilibrium effects are significant. In this work, an e-ph coupling model is proposed by transforming the full scattering terms into relaxation time approximation forms in the coupled electron and phonon Boltzmann transport equations. Consequently, the non-equilibrium effects are included in the calculation of e-ph coupling constant. The coupling model is verified by modeling the ultrafast dynamics in femtosecond pump-probe experiments on metal surface, which shows consistent results with the full integral treatment of scattering terms. The e-ph coupling constant is strongly reduced due to both the temporal non-equilibrium between different phonon branches and the spatial non-equilibrium of electrons in confined space. The present work will promote not only a fundamental understanding of the e-ph coupling constant but also the theoretical description of coupled electron and phonon transport at micro- and nanoscale.
