Thermal crossover from a Chern insulator to a fractional Chern insulator in pentalayer graphene

A recent experiment in pentalayer graphene/hBN moir\'e superlattices uncovered a surprising new phase, with integer quantization at fractional fillings, emerging at lower temperatures than the previously observed FQAHE states. Through theoretical analysis of the transport data, the authors establish here that this low-temperature phase is likely a disorder-induced localized insulating phase, and that the transition between this phase and the higher temperature FQAHE phase is a crossover phenomenon driven by the competition between interaction and disorder energy scales.