Ground and excited states of coupled exciton liquids in electron-hole quadrilayers

TL;DR

This paper investigates the properties of coupled exciton liquids in electron-hole quadrilayers, analyzing ground states, correlations, collective modes, and polaron behavior using a hypernetted chain approach.

Contribution

It introduces a theoretical study of interlayer exciton interactions in quadrilayers, including phase transitions and polaron effects, using a hypernetted chain formalism.

Findings

Computed ground state energies and pair correlation functions.

Estimated critical density for biexciton phase transition.

Analyzed exciton-polaron energies and effective masses.

Abstract

Interlayer excitons are bound states of electrons and holes confined in separate two-dimensional layers. Due to their repulsive dipolar interaction, interlayer excitons can form a correlated liquid. If another electron-hole bilayer is present, excitons from different bilayers can exhibit mutual attraction. We study such a quadrilayer system by a hypernetted chain formalism. We compute ground state energies, pair correlation functions, and collective mode velocities as functions of the exciton densities. We estimate the critical density for the transition to a paired biexciton phase. For a strongly unbalanced (unequal density) system, the excitons in the more dilute bilayer behave as polarons. We compute energies and effective masses of such exciton-polarons.