论文标题
微观散射对单层石墨烯中第三次谐波产生的影响
The effects of microscopic scattering on terahertz third harmonic generation in monolayer graphene
论文作者
论文摘要
由于其线性分散，单层石墨烯有望在Terahertz频率下产生第三个谐波响应。有多种不同的模型，最近已经在实验上观察到了这种效果。但是，关于散射对石墨烯中谐波产生的作用仍然存在很大的不确定性。在这项工作中，我们通过在长度仪表中采用最近的邻居紧密结合模型，以THZ频率对第三次谐波产生进行建模。我们在微观水平上包括光学声子和中性杂质散射，并检查散射对第三个谐波响应的影响。我们还使用从模拟中提取的场依赖性散射时间比较了现象学半经典理论的结果，并找到了比从微观模型中发现的明显低的第三个谐波场。这表明，第三次谐波对散射的性质比线性响应更为敏感。我们还将完整模拟的结果与最新的实验结果进行了比较，并找到定性协议。
Due to its linear dispersion, monolayer graphene is expected to generate a third harmonic response at terahertz frequencies. There have been a variety of different models of this effect and recently it has been experimentally observed. However, there is still considerable uncertainty as to the role of scattering on harmonic generation in graphene. In this work, we model third-harmonic generation in doped monolayer graphene at THz frequencies by employing a nearest-neighbour tight-binding model in the length gauge. We include optical phonon and neutral impurity scattering at the microscopic level, and examine the effects of scattering on the third harmonic response. We also compare the results of a phenomenological semiclassical theory, using a field-dependent scattering time extracted from the simulation, and find a significantly lower third harmonic field than that found from the microscopic model. This demonstrates that third-harmonic generation is much more sensitive to the nature of the scattering than is the linear response. We also compare the results of our full simulation to recent experimental results and find qualitative agreement.
