Structure of exciton condensates in imbalanced electron-hole bilayers

TL;DR

This paper explores the phase diagram and pairing mechanisms of excitonic superfluidity in electron-hole bilayers, considering density imbalance and screening effects, and discusses potential symmetry breaking in the ground state.

Contribution

It provides a comprehensive phase diagram analysis across parameter space and detailed descriptions of the pairing wavefunction, advancing understanding of exciton condensates.

Findings

Resolved differences in previous literature on phase regions

Detailed characterization of the Fulde-Ferrell-Larkin-Ovchinnikov state

Discussion of spontaneous symmetry breaking possibilities

Abstract

We investigate the possibility of excitonic superfluidity in electron-hole bilayers. We calculate the phase diagram of the system for the whole range of electron-hole density imbalance and for different degrees of electrostatic screening, using mean-field theory and a Ginzburg-Landau expansion. We are able to resolve differences on previous work in the literature which concentrated on restricted regions of the parameter space. We also give detailed descriptions of the pairing wavefunction in the Fulde-Ferrell-Larkin-Ovchinnikov paired state. The Ginzburg-Landau treatment allows us to investigate the energy scales involved in the pairing state and discuss the possible spontaneous breaking of two-dimensional translation symmetry in the ground state.