Strong Correlation Driven Quadrupolar to Dipolar Exciton Transitions in a Trilayer Moir\'e Superlattice

TL;DR

This paper demonstrates how strong electronic correlations in trilayer moiré superlattices enable controlled transitions between quadrupolar and dipolar excitons, revealing new quantum phases and excitonic behaviors.

Contribution

It introduces a method to manipulate excitonic states via electron correlations and doping, advancing understanding of correlated excitons in moiré systems.

Findings

Controlled exciton transitions driven by doping and density.

Observation of strong exciton-electron interactions.

Potential for engineering many-body quantum phases.

Abstract

The additional layer degree of freedom in trilayer moir\'e superlattices of transition metal dichalcogenides enables the emergence of novel excitonic species, such as quadrupolar excitons, which exhibit unique excitonic interactions and hold promise for realizing intriguing excitonic phases and their quantum phase transitions. Concurrently, the presence of strong electronic correlations in moir\'e superlattices, as exemplified by the observations of Mott insulators and generalized Wigner crystals, offers a direct route to manipulate these new excitonic states and resulting collective excitonic phases. Here, we demonstrate that strong exciton-exciton and electron-exciton interactions, both stemming from robust electron correlations, can be harnessed to controllably drive transitions between quadrupolar and dipolar excitons. This is achieved by tuning either the exciton density or electrostatic doping in a trilayer semiconducting moir\'e superlattice. Our findings not only advance the fundamental understanding of quadrupolar excitons but also usher in new avenues for exploring and engineering many-body quantum phenomena through novel correlated excitons in semiconducting moir\'e systems.