论文标题
使用圆形极化光在有偏双层石墨烯中的山谷极化
Valley-polarization in biased bilayer graphene using circularly polarized light
论文作者
论文摘要
对于任何Valleytronic设备来说，实现两个不等山谷之间的人口失衡是至关重要的第一步。可以使用圆形极化光在有偏双层石墨烯中诱导山谷极化。在本文中，我们提出了一项详细的理论研究，该研究对偏置双层石墨烯中的山谷极化。我们表明，通过正确选择外部偏见和脉冲频率，可以实现几乎完美的山谷极化。我们发现，最佳脉冲频率$ω$由$ \hbarΩ= 2A给出，其中$ 2a $是石墨烯层之间的势能差。我们还发现，山谷极化不是源自狄拉克点本身，而是来自每个国家周围的状态。发现间隔散射可大大减少高频脉冲的山谷极化。发现热种群可显着减少小偏见的山谷极化。这项工作提供了对双层石墨烯中山谷极化的起源的洞察力，并将帮助寻求在实验室中研究山谷极化的实验者。
Achieving a population imbalance between the two inequivalent valleys is a critical first step for any valleytronic device. A valley-polarization can be induced in biased bilayer graphene using circularly polarized light. In this paper, we present a detailed theoretical study of valley-polarization in biased bilayer graphene. We show that a nearly perfect valley-polarization can be achieved with the proper choices of external bias and pulse frequency. We find that the optimal pulse frequency $ω$ is given by $\hbarω=2a,$ where $2a$ is the potential energy difference between the graphene layers. We also find that the valley-polarization originates not from the Dirac points themselves, but rather from a ring of states surrounding each. Intervalley scattering is found to greatly reduce the valley-polarization for high frequency pulses. Thermal populations are found to significantly reduce the valley-polarization for small biases. This work provides insight into the origin of valley-polarization in bilayer graphene and will aid experimentalists seeking to study valley-polarization in the lab.
