Electrical Reservoirs for Bilayer Excitons
Abstract
The ground state of two-dimensional (2D) electron systems with equal low densities of electrons and holes in nearby layers is an exciton fluid. We show that a reservoir for excitons can be established by contacting the two layers separately and maintaining the chemical potential difference at a value less than the spatially indirect band gap. Equilibration between the exciton fluid and the contacts proceeds via a process involving virtual intermediate states in which an unpaired electron or hole occupies a free carrier state in one of the 2D layers. We derive an approximate relationship between the exciton-contact equilibration rate and the electrical conductances between the contacts and individual 2D layers when the contact chemical potentials align with the free-carrier bands, and explain how electrical measurements can be used to measure thermodynamic properties of the exciton fluid.
Cite
@article{arxiv.1712.02751,
title = {Electrical Reservoirs for Bilayer Excitons},
author = {Ming Xie and Allan H. MacDonald},
journal= {arXiv preprint arXiv:1712.02751},
year = {2018}
}
Comments
Minor revision of v1. Accepted by PRL