论文标题
在掺杂双层石墨烯中应用的掺杂系统中的光活性理论
Theory of Optical Activity in Doped Systems with Application to Twisted Bilayer Graphene
论文作者
论文摘要
我们从理论上研究了掺杂系统中的光活性，并从光波向量依赖性线性光导率中得出光活性张量。尽管通过最小耦合的哈密顿量通过速度量规引入轻度 - 互动，但我们发现，如果有限的有效的汉密尔顿（Hamiltonian）（例如，几个频带紧密结合模型），可以在实践中避免众所周知的``错误的分歧''问题。我们为光活性张量获得的表达与最新的理论是良好的数值一致性，该理论是针对不符合的拓扑上琐事的系统的。我们将理论应用于封闭式扭曲的双层石墨烯的光学活动，并详细讨论了结果对扭角，化学电位，栅极电压和旋转中心的位置的依赖性，形成了扭曲的双层石墨烯。
We theoretically study the optical activity in a doped system and derive the optical activity tensor from a light wavevector-dependent linear optical conductivity. Although the light-matter interaction is introduced through the velocity gauge from a minimal coupling Hamiltonian, we find that the well-known ``false divergences'' problem can be avoided in practice if the electronic states are described by a finite band effective Hamiltonian, such as a few-band tight-binding model. The expression we obtain for the optical activity tensor is in good numerical agreement with a recent theory derived for an undoped topologically trivial gapped system. We apply our theory to the optical activity of a gated twisted bilayer graphene, with a detailed discussion of the dependence of the results on twist angle, chemical potential, gate voltage, and location of rotation center forming the twisted bilayer graphene.
