Collective optical properties of moir\'e excitons

TL;DR

This paper explores how moiré excitons in transition metal dichalcogenide bilayers exhibit collective optical properties that can probe correlated electron states and charge orders, extending beyond current optical lattice capabilities.

Contribution

It introduces the concept that moiré excitons can be used to investigate collective radiative effects and correlated electron states without subwavelength resolution.

Findings

Moiré excitons extend optical properties to deep subwavelength scales.

Collective optical properties can reveal electronic charge orderings.

Wigner crystal states influence excitonic band structures and Berry curvature.

Abstract

We propose that excitons in moir\'e transition metal dichalcogenide bilayers offer a promising platform for investigating collective radiative properties. While some of these optical properties resemble those of cold atom arrays, moir\'e excitons extend to the deep subwavelength limit, beyond the reach of current optical lattice experiments. Remarkably, we show that the collective optical properties can be exploited to probe certain correlated electron states without requiring subwavelength spatial resolution. Specifically, we illustrate that the Wigner crystal states of electrons doped into these bilayers act as an emergent periodic potential for excitons. Moreover, the collective dissipative excitonic bands and their associated Berry curvature can reveal various charge orders that emerge at the corresponding electronic doping. Our study provides a promising pathway for future research on the interplay between collective effects and strong correlations involving moir\'e excitons.