On the Optical Properties of Excitons in Buckled 2D Materials in an External Electric Field

TL;DR

This study investigates how external electric fields influence the excitonic binding energies and optical properties in buckled 2D materials like silicene, germanene, and stanene, revealing the importance of potential models and material parameters.

Contribution

It introduces a detailed analysis of exciton behavior under electric fields in Xenes, highlighting the impact of potential choice and material parameters on excitonic properties.

Findings

Electric fields can tune exciton energies and optical properties.

Differences in interaction potentials significantly affect eigenenergies.

Material parameters critically influence exciton binding energies.

Abstract

We study the binding energies and optical properties of direct and indirect excitons in monolayers and double layer heterostructures of Xenes: silicene, germanene, and stanene. It is demonstrated that an external electric field can be used to tune the eigenenergies and optical properties of excitons by changing the effective mass of charge carriers. The Schr\"{o}dinger equation with field-dependent exciton reduced mass is solved by using the Rytova-Keldysh (RK) potential for direct excitons, while both the RK and Coulomb potentials are used for indirect excitons. It is shown that for indirect excitons, the choice of interaction potential can cause huge differences in the eigenenergies at large electric fields and significant differences even at small electric fields. Furthermore, our calculations show that the choice of material parameters has a significant effect on the binding energies and optical properties of direct and indirect excitons. These calculations contribute to the rapidly growing body of research regarding the excitonic and optical properties of this new class of two dimensional semiconductors.