Terahertz-induced high-order harmonic generation and nonlinear charge transport in graphene
Terahertz-induced high-order harmonic generation and nonlinear charge transport in graphene
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DOI：
10.1103/physrevb.106.024313
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发表时间：
2022-03
影响因子：
3.7
通讯作者：
Wen-Hao Mao;Á. Rubio;S. A. Sato
中科院分区：
文献类型：
--
作者：
Wen-Hao Mao;Á. Rubio;S. A. Sato
基于驰豫时间近似的量子主方程，从理论上研究了太赫兹引起的石墨烯的高次谐波产生和非线性电输运。为了获得对这一现象的微观洞察，我们将完全动态计算的结果与准静态近似下的结果进行了比较，在准静态近似下，电子系统被近似为非平衡稳态。因此，我们fi发现，在石墨烯中太赫兹诱导的电子动力学可以用每个情况下的非平衡稳态精确地模拟。布居分布分析进一步表明，石墨烯中太赫兹引起的高次谐波是由于布里渊区电子的大位移导致有效电导率降低所致。fi分析进一步证实了太赫兹引起的高次谐波是由于布里渊区电子的大量位移引起的。通过比较目前的非平衡图和热力学图，我们探索了电子动力学的非平衡性在石墨烯中极端非线性光学和输运现象中的作用。
We theoretically study the terahertz-induced high-order harmonic generation (HHG) and nonlinear electric transport in graphene based on the quantum master equation with the relaxation time approximation. To obtain microscopic insight into the phenomena, we compare the results of the fully dynamical calculations with those under a quasistatic approximation, where the electronic system is approximated as a nonequilibrium steady state. As a result, we find that the THz-induced electron dynamics in graphene can be accurately modeled with the nonequilibrium steady state at each instance. The population distribution analysis further clarifies that the THz-induced HHG in graphene originates from the reduction of effective conductivity due to a large displacement of electrons in the Brillouin zone. By comparing the present nonequilibrium picture with a thermodynamic picture, we explore the role of the nonequilibrium nature of electron dynamics on the extremely nonlinear optical and transport phenomena in graphene.