Exciton Polariton-Polariton Interactions in Transition-Metal Dichalcogenides

TL;DR

This study provides a detailed, material-specific analysis of exciton polariton interactions in MoS₂ monolayers and homobilayers within a cavity, highlighting exchange, saturation, and dipole-dipole effects crucial for polaritonic device development.

Contribution

It introduces a predictive, microscopic approach to characterize many-body polariton interactions in transition-metal dichalcogenides, emphasizing exchange and dipole-dipole contributions.

Findings

Exchange interaction causes asymmetric energy shifts in polariton branches.

Temperature and electron-photon coupling influence energy renormalization.

Dipole-dipole interaction enables electrical control of polariton properties.

Abstract

Microscopic insights into nonlinear interactions are essential for advancing polaritonic devices. Existing studies often rely on phenomenological models that overlook important many-body processes. Based on a material-specific and predictive approach, we investigate monolayer and homobilayer MoS$_2$ embedded in a Fabry-P\'erot cavity to characterize the exchange, saturation, and dipole-dipole contributions to polariton-polariton interactions in these technologically promising materials. A key finding is that the exchange interaction induces asymmetric energy shifts of the lower and upper polariton branches in a detuned cavity, a behavior driven by the difference in their excitonic character. Furthermore, we demonstrate that temperature and electron-photon coupling determine the energy renormalization through the equilibrium polariton distribution. In homobilayers, the dipole-dipole interaction is mediated by the interlayer character, enabling electrical control and facilitating the electric-field-induced closing of anti-crossings due to dipolar-interaction shifts. The gained insights on polariton-polariton interactions are important for the development of ultra-compact polaritonic circuitry.