Impact of an electron Wigner crystal on exciton propagation

TL;DR

This paper investigates how a Wigner crystal of electrons in 2D materials influences exciton propagation, revealing significant effects on transport properties despite minimal energy shifts, and offers a theoretical framework for exciton-charge order interactions.

Contribution

It provides a microscopic understanding of exciton behavior in the presence of a Wigner crystal, highlighting the impact on exciton transport and establishing a new theoretical approach.

Findings

Wigner crystal electrons significantly affect exciton propagation

Exciton energy remains largely unaffected by the Wigner crystal

Carrier density and temperature tune exciton transport effects

Abstract

The strong Coulomb interaction in 2D materials facilitates the formation of tightly bound excitons and charge-ordered phases of matter. A prominent example is the formation of a crystalline phase from free charges due to mutual Coulomb repulsion, known as the Wigner crystal. While exciton-electron interactions have been used as a sensor for Wigner crystallization, its impact on exciton properties has been poorly understood so far. Here, we show that the weak potential induced by periodically ordered Wigner crystal electrons has a major impact on exciton propagation, albeit having only a minor influence on exciton energy. The effect is tunable with carrier density determining the Wigner crystal confinement and temperature via thermal occupation of higher subbands. Our work provides microscopic insights into the interplay between excitons and charge-ordered states identifying key signatures in exciton transport, and establishes a theoretical framework for understanding exciton propagation in the presence of strong electronic correlations.