Enhanced scattering between electrons and exciton-polaritons in a microcavity

TL;DR

This paper develops a theoretical model showing that electron-polariton scattering is significantly enhanced in a microcavity due to strong light-matter coupling, with potential implications for tunable interactions in optoelectronics.

Contribution

It introduces an analytic formalism for exciton-polariton propagators in a 2D semiconductor microcavity, revealing enhanced scattering effects and resonance features.

Findings

Electron-polariton scattering is strongly enhanced compared to exciton-electron interactions.

Strong light-matter coupling shifts collision energy, leading to counter-intuitive interaction enhancement.

Lack of Galilean invariance causes narrow resonance-like features near the polariton inflection point.

Abstract

The interplay between strong light-matter interactions and charge doping represents an important frontier in the pursuit of exotic many-body physics and optoelectronics. Here, we consider a simplified model of a two-dimensional semiconductor embedded in a microcavity, where the interactions between electrons and holes are strongly screened, allowing us to develop a diagrammatic formalism for this system with an analytic expression for the exciton-polariton propagator. We apply this to the scattering of spin-polarized polaritons and electrons, and show that this is strongly enhanced compared with exciton-electron interactions. As we argue, this counter-intuitive result is a consequence of the shift of the collision energy due to the strong light-matter coupling, and hence this is a generic feature that applies also for more realistic electron-hole and electron-electron interactions. We furthermore demonstrate that the lack of Galilean invariance inherent in the light-matter coupled system can lead to a narrow resonance-like feature for polariton-electron interactions close to the polariton inflection point. Our results are potentially important for realizing tunable light-mediated interactions between charged particles.