论文标题
$ \ textit {ab intib} $四波段Wannier Wannier紧密结合模型，用于通用扭曲的石墨烯系统
$\textit{Ab initio}$ four-band Wannier tight-binding model for generic twisted graphene systems
论文作者
论文摘要
新实现的扭曲石墨烯系统，例如扭曲的双层石墨烯（TBG），扭曲的双重双层石墨烯（TDBG）和扭曲的三层石墨烯（TTG）吸引了广泛的理论关注。因此，系统的简单准确模型对于进一步的研究至关重要。在这里，我们构建了对称性适应的局部Wannier函数，以及相应的$ \ textit {ab intio} $最小的两种valley四波段有效的紧密结合模型，用于具有较小扭曲角度的通用扭曲石墨烯系统。这种两谷模型逃避了一谷模型中脆弱的拓扑引起的障碍物。引入了真实的太空谷操作员，以明确描述Valley $ U_ {V} \ left（1 \右）$对称。每个适应对称性的Wannier轨道均显示出一个奇特的三峰形式，其最大值在AA斑点，其中心位于AB或BA斑点。还给出了扩展的哈伯德模型，并明确显示相关参数。我们提供了一种系统地构建通用扭曲石墨烯系统的Wannier紧密结合模型的方法。我们的模型为进一步研究这些系统中的多体效应提供了坚定的基础。
The newly realized twisted graphene systems such as twisted bilayer graphene (TBG), twisted double bilayer graphene (TDBG), and twisted trilayer graphene (TTG) have attracted widespread theoretical attention. Therefore, a simple and accurate model of the systems is of vital importance for the further study. Here, we construct the symmetry-adapted localized Wannier functions and the corresponding $\textit{ab initio}$ minimal two-valley four-band effective tight-binding models for generic twisted graphene systems with small twist angle. Such two-valley model evades the Wannier obstruction caused by the fragile topology in one-valley model. The real space valley operator is introduced to explicitly describe the valley $U_{v}\left(1\right)$ symmetry. Each symmetry-adapted Wannier orbital shows a peculiar three-peak form with its maximum at AA spots and its center at AB or BA spots. An extended Hubbard model is also given and the related parameters are presented explicitly. We provide an approach to systematically build the Wannier tight-binding model for generic twisted graphene systems. Our model provides a firm basis for further study of the many-body effects in these systems.
