论文标题
带式隧道对材料传输特性的影响使用第一原理Wigner分布
Interband tunneling effects on materials transport properties using the first principles Wigner distribution
论文作者
论文摘要
狭窄间隙半导体中的电子传输的特征是价值和传导带之间的自发垂直转变，这一现象也称为Zener隧道。但是，基于Boltzmann传输方程的现有模型不会捕获这种效果。在这项工作中，我们提出了使用Wigner分布函数的电子传输的新的完全第一原理模型，并实施它以求解电子运动方程。形式主义将Boltzmann方程推广到具有强带耦合的材料，并包括电荷电流运算符的外部分子组件的运输贡献。我们通过研究BI $ _2 $ SE $ _3 $的研究来说明方法，这表明，带间隧道在实验相关的小型掺杂浓度上占主导地位的电子传输动力学，这种行为可能与其他半导体共享，包括拓扑绝缘体。令人惊讶的是，齐纳隧道也发生在频带subvalleys之间，这些能量比带隙大得多。
Electronic transport in narrow gap semiconductors is characterized by spontaneous vertical transitions between carriers in the valence and conduction bands, a phenomenon also known as Zener tunneling. However, this effect is not captured by existing models based on the Boltzmann transport equation. In this work, we propose a new fully first principles model for electronic transport using the Wigner distribution function and implement it to solve the equations of motion for electrons. The formalism generalizes the Boltzmann equation to materials with strong interband coupling and include transport contributions from off-diagonal components of the charge current operator. We illustrate the method with a study of Bi$_2$Se$_3$, showing that interband tunneling dominates the electron transport dynamics at experimentally relevant small doping concentrations, a behavior that is likely shared with other semiconductors, including topological insulators. Surprisingly, Zener tunneling occurs also between band subvalleys separated by energy much larger than the band gap.
