Effect of exciton-phonon coupling on the interlayer excitons in transition metal dichalcogenides double layers

TL;DR

This paper studies how exciton-phonon interactions affect the binding energy of interlayer excitons in transition metal dichalcogenide double layers, revealing significant energy shifts and implications for exciton condensation.

Contribution

It introduces a theoretical analysis of exciton-phonon coupling effects on interlayer excitons using Lee-Low-Pines transformation, highlighting energy corrections and enhanced condensation conditions.

Findings

Binding energy varies by tens of meV depending on material and interlayer distance.

Exciton-phonon coupling increases the critical temperature for exciton condensation.

Results suggest potential for Bose-Einstein condensation and superfluidity in 2D heterostructures.

Abstract

We investigate the correction of interlayer exciton binding energy in transition metal dichalcogenides double layers arising from the exciton-optical phonon coupling using the method of Lee-Low-Pines unitary transformation. We find that the binding energy varies in several tens of meV, depending on the polarizability of materials and interlayer distance between double layers. Moreover, the correction of binding energy results in the remarkable increasing of the critical temperature for the condensation of dilute excitonic gas basing on the Berezinskii-Kosterlitz-Thouless model. These results not only enrich the knowledge for the modulation of interlayer exciton, but also provide potential insights for the Bose-Einstein condensation and superfluid transport of interlayer exciton in two-dimensional heterostructures.