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arXiv · 1712.02751

Electrical Reservoirs for Bilayer Excitons

Ming Xie·Allan H. MacDonald
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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.

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Ming Xie, Allan H. MacDonald. 2018-08-08. Electrical Reservoirs for Bilayer Excitons. https://doi.org/10.1103/physrevlett.121.067702

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