  We theoretically investigate the localization mechanism of quantum anomalous
Hall Effect (QAHE) with large Chern numbers $\mathcal{C}$ in bilayer graphene
and magnetic topological insulator thin films, by applying either nonmagnetic
or spin-flip (magnetic) disorders. We show that, in the presence of nonmagnetic
disorders, the QAHEs in both two systems become Anderson insulating as expected
when the disorder strength is large enough. However, in the presence of
spin-flip disorders, the localization mechanisms in these two host materials
are completely distinct. For the ferromagnetic bilayer graphene with Rashba
spin-orbit coupling, the QAHE with $\mathcal{C}=4$ firstly enters a
Berry-curvature mediated metallic phase, and then becomes localized to be
Anderson insulator along with the increasing of disorder strength. While in
magnetic topological insulator thin films, the QAHE with $\mathcal{C=N}$
firstly enters a Berry-curvature mediated metallic phase, then transitions to
another QAHE with ${\mathcal{C}}={\mathcal{N}}-1$ along with the increasing of
disorder strength, and is finally localized to the Anderson insulator after
${\mathcal{N}}-1$ cycling between the QAHE and metallic phases. For the unusual
findings in the latter system, by analyzing the Berry curvature evolution, it
is known that the phase transitions originate from the exchange of Berry
curvature carried by conduction (valence) bands. At the end, we provide a
phenomenological picture related to the topological charges to help understand
the underlying physical origins of the two different phase transition
mechanisms.
