Anomalous Chern insulators in Twisted M+N multilayer graphene.

Twisted multilayer graphene offers an unprecedented opportunity to design strongly correlated phases with nontrivial momentum-space topology. One of these phases is the anomalous Hall effect that features quantized Hall conductivity at zero magnetic field and, when doped to fractional fillings, can host quasiparticles with nontrivial statistics. Recent experimental progress on rhombohedral multilayer graphene defies conventional wisdom by showing that these anomalous Hall insulators can unexpectedly arise in systems that do not a priori have isolated narrow Chern bands. Instead, the flat Chern bands are primarily produced by Coulomb interactions. Inspired by this insight, we re-examine the mean-field phase diagram of twisted M+N multilayer graphene in the large-displacement-field limit. We find that these systems also host narrow Chern bands that spontaneously form due Hartree-Fock renormalization. Therefore, we suggest that these platforms may also be fertile playgrounds for discovering fractional Chern insulators.