  Two dimensional materials subject to long-wavelength modulations have emerged
as novel platforms to study topological and correlated quantum phases. In this
article, we develop a versatile and computationally inexpensive method to
predict the topological properties of materials subjected to a superlattice
potential by combining degenerate perturbation theory with the method of
symmetry indicators. In the absence of electronic interactions, our analysis
provides a systematic rule to find the Chern number of the superlattice-induced
miniband starting from the harmonics of the applied potential and a few
material-specific coefficients. Our method also applies to anomalous
(interaction-generated) bands, for which we derive an efficient algorithm to
determine all Chern numbers compatible with a self-consistent solution to the
Hartree-Fock equations. Our approach gives a microscopic understanding of the
quantum anomalous Hall insulators recently observed in rhombohedral graphene
multilayers.
