Exchange and correlation effects on drag in low density electron bilayers: Coulomb and virtual-optical-phonon-mediated electron-electron interaction

TL;DR

This paper studies how exchange, correlation, and virtual polar optical phonons influence electron-electron interactions and drag in low-density bilayer systems, improving agreement with experimental data.

Contribution

It introduces the combined effects of exchange-correlation and virtual phonon interactions on Coulomb drag, providing new insights into low-density electron bilayers.

Findings

Exchange-correlation significantly enhances transresistivity.

Virtual phonon interactions reduce total drag.

Results align better with recent experiments.

Abstract

We investigate the effect of exchange and correlation (xc) in low-density electron bilayers. Along with the direct Coulomb interaction, the effective electron-electron interaction mediated by the exchange of virtual polar optical (PO) phonons is considered. We find that the introduction of xc corrections results in a significant enhancement of the transresistivity and qualitative changes in its temperature dependence. The virtual PO-phonon contribution behaves similarly to the Coulomb drag and reduces noticeably the total drag thereby resulting in a better agreement with the recent experimental findings.