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arXiv 2012.15129cond-mat.mes-hall
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金属中电子-声子耦合常数的非平衡效应

Non-equilibrium effects on electron-phonon coupling constant in metals

Wuli Miao, Moran Wang

摘要:

了解金属中电子和声子之间的能量交换对于微纳米制造和系统设计非常重要。电子-声子(e-ph)耦合常数是描述这种交换强度,但它的变化仍然不清楚在微米和纳米级的非平衡效应是显着的。本文通过将电子-声子耦合玻尔兹曼输运方程中的全散射项转化为弛豫时间近似形式,提出了一个e-ph耦合模型。因此,在计算e-ph耦合常数时考虑了非平衡效应。通过对金属表面飞秒抽运探测实验中的超快动力学过程进行模拟,验证了耦合模型的正确性,结果与散射项的全积分处理一致。由于不同声子分支之间的时间非平衡和受限空间中电子的空间非平衡,e-ph耦合常数强烈减小。本工作不仅将促进对e-ph耦合常数的基本理解,而且将促进对微纳米尺度下耦合电子和声子输运的理论描述。

英文摘要:

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.

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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