论文标题
非极性半导体中的两次散射：SI中温暖电子传输的第一原理研究
Two-phonon scattering in non-polar semiconductors: a first-principles study of warm electron transport in Si
论文作者
论文摘要
半导体中电荷转运的AB-INITIO理论通常采用最低的扰动理论，其中电子与一个声子（1PH）相互作用。该理论被认为足以解释非极性半导体的低场迁移率，但尚未对低场制度进行广泛的测试。在这里，我们报告了温暖电子系数$β$所述的SI电子迁移率的电场依赖性的第一原理计算。尽管1PH理论高估了低场迁移率仅约20％，但它在一定温度和晶体学轴上高估了$β$的两个倍。我们表明，$β$中的差异是通过包含壳上的迭代迭代2-PHONON（2PH）散射过程来调和的，这表明即使在非偏置半导体中，来自高阶电子 - phonon相互作用的散射也是不可忽略的。此外，约有20％低估了具有2PH散射的低场迁移率，表明在电子 - 波相互作用的扰动膨胀中可能会发生非平凡的取消。
The ab-initio theory of charge transport in semiconductors typically employs the lowest-order perturbation theory in which electrons interact with one phonon (1ph). This theory is accepted to be adequate to explain the low-field mobility of non-polar semiconductors but has not been tested extensively beyond the low-field regime. Here, we report first-principles calculations of the electric field-dependence of the electron mobility of Si as described by the warm electron coefficient, $β$. Although the 1ph theory overestimates the low-field mobility by only around 20%, it overestimates $β$ by over a factor of two over a range of temperatures and crystallographic axes. We show that the discrepancy in $β$ is reconciled by inclusion of on-shell iterated 2-phonon (2ph) scattering processes, indicating that scattering from higher-order electron-phonon interactions is non-negligible even in non-polar semiconductors. Further, a ~20% underestimate of the low-field mobility with 2ph scattering suggests that non-trivial cancellations may occur in the perturbative expansion of the electron-phonon interaction.
