Topological Floquet flat bands in irradiated alternating twist multilayer graphene

We study the appearance of topological Floquet flat bands in alternating-twist multilayer graphene, which has alternating relative twist angle +/- 0 near the first magic angle. While the system hosts both flat bands and a steep Dirac cone in the static case, the circularly polarized laser beam can open a gap at the Moire K point and create Floquet flat bands carrying nonzero Chern numbers. Considering recent lattice-relaxation results, we find that the topological flat band is well-isolated for the effective interlayer tunneling inn = 3, 4, 5 layers. Such dynamically produced topological flat bands are potentially observed in the experiment and thus provide a feasible way to realize the fractional Chern insulator.

Automated summary

We study the emergence of topological Floquet flat bands in alternating-twist multilayer graphene near the first magic angle. By applying a circularly polarized laser beam, a gap can be opened at the Moire K point, creating Floquet flat bands with non-zero Chern numbers. These dynamically produced topological flat bands can potentially be observed in experiments and offer a feasible way to realize the fractional Chern insulator.