  Enhancement of the dielectric response of insulators by disorder is
theoretically proposed, where the quantum interference of electronic waves
through the nanoscale/mesoscopic system and its change due to external
perturbations control the polarization. In the disordered case with all the
states being localized, the resonant tunneling, which is topologically
protected, plays a crucial role, and enhances the dielectric response by a
factor 30~40 compared with the pure case. Realization of this idea with
accessible materials/structures is also discussed.
