Dirac Magic Angles and Topological Floquet Flat Bands in Twisted Multilayer graphene

We characterize the energy and quasienergy (Floquet) bands in various twisted multilayer graphene structures. We find new magic angles in the static AA-stacked structures that we name “Dirac magic angles” in which multiple Dirac cones from different bands coexist at magic twist angles. We also find Floquet flat bands carrying non-zero Chern numbers in the irradiated AB-stacked and twist-and-twist back structures. The Dirac magic angles may offer a new platform to study the itinerant electron magnetism or robust superconductivity controlled by the twist angles. The dynamically produced topological flat bands under irradiation can potentially realize the fractional Chern insulator.