Tunable properties of excitons in double monolayer semiconductor heterostructures

TL;DR

This paper investigates how the exciton properties in double monolayer TMD heterostructures can be tuned by adjusting the spacer width and dielectric environment, using a novel Chebyshev polynomial expansion method.

Contribution

It introduces a new computational approach to solve the Wannier equation for excitons and systematically studies the effects of dielectric and geometric parameters on exciton binding energies.

Findings

Inter- and intralayer exciton binding energies depend on spacer width and dielectric constant.

Exciton energy and wave function are sensitive to geometric configuration and bandgap corrections.

Method allows accurate modeling of exciton properties in layered TMD heterostructures.

Abstract

We studied the exciton properties in double layers of transition metal dichalcogenides (TMDs) with a dielectric spacer between the layers. We developed a method based on an expansion of Chebyshev polynomials to solve the Wannier equation for the exciton. Corrections to the quasiparticle bandgap due to the dielectric environment were also included via the exchange self-energy calculated within a continuum model. We systematically investigated hetero double-layer systems for TMDs with chemical compounds MX2, showing the dependence of the inter- and intralayer excitons binding energies as a function of the spacer width and the dielectric constant. Moreover, we discussed how the exciton energy and its wave function, which includes the effects of the changing bandgap, depend on the geometric system setup.