Flatband localization in disordered one-dimensional moiré photonic crystal bilayers.

Abstract

Flatband wave localization is a hallmark phenomenon in moiré photonic crystals and offers a new route to tight light confinement. However, the influence of structural disorder on flatband light localization has remained largely unexplored. In this work, we investigate one-dimensional moiré photonic crystal bilayers and demonstrate that magic distances - specific interlayer separations at which the bandwidth of an optical band is sharply minimized - remain well defined even in the presence of disorder. To address the high computational cost of direct electromagnetic simulations, we introduce a tight-binding model for moiré photonic crystal bilayers, which quantitatively reproduces flatband formation, bandwidth narrowing at magic distances, and localization properties over a wide parameter space. By examining a large ensemble of distorted photonic crystals, we find that wave localization accompanied by sharp bandwidth narrowing can be recovered in each realization by tuning the interlayer separation, even under disorder. The robustness of magic distances provides an encouraging foundation for implementing photonic devices based on moiré light confinement.