Exciton formation in strongly correlated electron-hole systems near the semimetal-semiconductor transition

TL;DR

This paper investigates how excitons influence electron-hole correlations near the semimetal-semiconductor transition, revealing qualitative differences between weak and strong coupling regimes.

Contribution

It provides a detailed analysis of electron-hole-exciton correlations and their impact on the plasma near the excitonic insulator phase transition.

Findings

Differences in electron-hole correlations between weak and strong coupling regimes.

Quantitative calculations of bound and unbound electron-hole densities.

Identification of exciton influence on surrounding electron and hole distributions.

Abstract

The region surrounding the excitonic insulator phase is a three-component plasma composed of electrons, holes, and excitons. Due to the extended nature of the excitons, their presence influences the surrounding electrons and holes. We analyze this correlation. To this end, we calculate the density of bound electrons, the density of electrons in the correlated state, the momentum-resolved exciton density, and the momentum-resolved density of electron-hole pairs that are correlated but unbound. We find qualitative differences in the electron-hole correlations between the weak-coupling and the strong-coupling regime.