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Updated: May 11, 2025

Excitonic Hamiltonians for Calculating Optical Absorption Spectra and Optoelectronic Properties of Molecular Aggregates and Solids
Published on: May 27, 2020
Perfect Coulomb drag in a dipolar excitonic insulator
Phuong X Nguyen1,2, Liguo Ma1, Raghav Chaturvedi1
1School of Applied and Engineering Physics, Cornell University, Ithaca, NY, USA.
Abstract:
Excitonic insulators (EIs) are a solid-state prototype for bosonic phases of matter that can support charge-neutral exciton currents. However, demonstration of exciton transport in EIs is difficult. In this work, we show that the strong interlayer excitonic correlation at equal electron and hole densities in MoSe2/WSe2 double layers separated by a 2-nanometer barrier yields perfect Coulomb drag under zero magnetic field: A charge current in one layer induces an equal but opposite drag current in the other layer at low temperatures. The drag current ratio remains above 0.9 up to about 20 kelvin. As exciton density increases above the Mott density, the excitons dissociate into an electron-hole plasma abruptly, and only frictional drag is observed. Our experiment may lead to the realization of exciton circuitry and superfluidity.
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