We propose a tunable optical setup to engineer topologically nontrivial flat bands in twisted bilayer graphene under circularly polarized light. Using both analytical and numerical calculations, we demonstrate that nearly flat bands can be engineered at small twist angles near the magic angles of the static system. The flatness and the gaps between these bands can be tuned optically by varying laser frequency and amplitude. We study the effects of interlayer hopping variations on Floquet flat bands and find that changes associated with lattice relaxation favor their formation. Furthermore, we find that, once formed, the flat bands carry nonzero Chern numbers. We show that at currently known values of parameters, such topological flat bands can be realized using circularly polarized UV laser light. Thus, our work opens the way to creating optically tunable, strongly correlated topological phases of electrons in moiré superlattices.

中文翻译：

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辐照扭曲双层石墨烯中的球团工程拓扑平面带

我们提出了一种可调谐的光学装置，以在圆偏振光下扭曲双分子层石墨烯中构造拓扑上不平凡的平坦带。使用分析和数值计算，我们证明可以在接近静态系统的魔角的较小扭转角处设计出几乎平坦的频带。这些频带之间的平坦度和间隙可以通过改变激光频率和振幅来进行光学调节。我们研究了层间跳变对Floquet平坦带的影响，发现与晶格弛豫相关的变化有利于它们的形成。此外，我们发现，一旦形成，平坦带就会携带非零的Chern数。我们表明，在当前已知的参数值下，可以使用圆偏振UV激光实现这种拓扑平坦的波段。从而，