论文标题
扭曲的双层石墨烯在绝缘状态下的光学响应和非线性大厅响应
Optical response and nonlinear Hall response of twisted bilayer graphene in the insulating state
论文作者
论文摘要
在这项工作中，我们计算了绝缘状态中扭曲的双层石墨烯（TBG）的光学响应和非线性霍尔响应。考虑了不同的绝缘状态，包括自旋谷极化（SPVP）状态，自旋极化量子霍尔（SPQH）状态，自旋极化山谷霍尔（SPVH）状态和自旋极化Kramers-Intervalley Cooherence（SPKIVC）状态。我们计算了这四个状态的光导率（$σ_{xx} $），我们发现自旋valley极化状态显示了与其他三个状态不同的两峰特征。为了区分其他三个状态，我们计算了与浆果曲率偶极子成正比的非线性霍尔响应，我们发现浆果曲率偶极子的化学势依赖性可以区分这三个状态。我们的结果可以在光谱和运输实验中进行测试，并且可能有助于确定TBG中绝缘状态的性质。
In this work, we calculate the optical response and the nonlinear Hall response of twisted bilayer graphene (TBG) in the insulating states. Different insulating states, including spin-valley polarized (SPVP) state, spin-polarized quantum Hall(SPQH) state, spin-polarized valley Hall (SPVH) state, and spin polarized Kramers-intervalley coherence (SPKIVC) state, are considered. We calculate the optical conductivity ($σ_{xx}$) of these four states and we find that the spin-valley polarized state shows a two-peak feature which is different from the other three states. In order to distinguish the other three states, we calculate the nonlinear Hall response which is proportional to Berry curvature dipole, and we find the chemical potential dependence of the Berry curvature dipole can distinguish these three states. Our result can be tested in the spectroscopy and transport experiments and may be helpful to determine the nature of insulating state in TBG.
