论文标题
双层石墨烯中的拓扑和堆叠的平板带，具有超晶格电位
Topological and stacked flat bands in bilayer graphene with a superlattice potential
论文作者
论文摘要
我们表明，在存在2D超晶格电位的情况下，双层石墨烯可提供高度可调的设置，可以实现各种平坦的风带现象。我们专注于两个制度：（i）具有非零Chern数字C的拓扑平面带，包括Chern数字较高的频段| C | > 1; （ii）一个前所未有的相，该阶段由C = 0的几乎完美的平坦带组成。对于潜在和超晶格周期性的现实值，该堆栈可以跨越近100 MeV，几乎包括所有低能谱。我们进一步表明，在拓扑结构中，拓扑平面带具有有利的频带几何形状，用于实现分数Chern绝缘子（FCI），并使用精确的对角线化表明FCI实际上是1/3填充的基态。我们的结果为将来的实验提供了现实指南，以实现一个新的平面现象平台。
We show that bilayer graphene in the presence of a 2D superlattice potential provides a highly tunable setup that can realize a variety of flat band phenomena. We focus on two regimes: (i) topological flat bands with non-zero Chern numbers, C, including bands with higher Chern numbers |C| > 1; and (ii) an unprecedented phase consisting of a stack of nearly perfect flat bands with C = 0. For realistic values of the potential and superlattice periodicity, this stack can span nearly 100 meV, encompassing nearly all of the low-energy spectrum. We further show that in the topological regime, the topological flat band has a favorable band geometry for realizing a fractional Chern insulator (FCI) and use exact diagonalization to show that the FCI is in fact the ground state at 1/3 filling. Our results provide a realistic guide for future experiments to realize a new platform for flat band phenomena.
