Excitonic Superfluidity and Screening in Electron-Hole Bilayer Systems

TL;DR

This paper investigates excitonic superfluidity in electron-hole bilayer systems, comparing theoretical models with Monte-Carlo simulations to identify conditions for superfluidity and guide future device design.

Contribution

It demonstrates that the mean-field theory incorporating superfluid state screening aligns well with Monte-Carlo results, clarifying the role of screening in superfluidity predictions.

Findings

Excellent agreement between mean-field theory with superfluid screening and Monte-Carlo results.

Existing devices are unlikely to exhibit superfluidity based on the theory.

Provides guidance for designing new devices to achieve superfluidity.

Abstract

Superfluidity in e-h bilayers in graphene and GaAs has been predicted many times but not observed. A key problem is how to treat the screening of the Coulomb interaction for pairing. Different mean-field theories give dramatically different conclusions, and we test them against diffusion Monte-Carlo calculations. We get excellent agreement with the mean-field theory that uses screening in the superfluid state, but large discrepancies with the others. The theory predicts no superfluidity in existing devices and gives pointers for new devices to generate superfluidity.