Eur. Phys. J. B (2021) 94: 16
https://doi.org/10.1140/epjb/s10051-020-00030-6

Regular Article - Solid State and Materials

Binding energy and decaytime of exciton in dielectric medium

¹ Medical Imaging Techniques, Simav Vocational School of Health Services, Kutahya Health Sciences University, TR-43500, Kutahya, Turkey
² Department of Physics, Faculty of Science, Akdeniz University, TR-07058, Antalya, Turkey

^a abdullah.guvendi@ksbu.edu.tr

Received: 19 August 2020
Accepted: 20 November 2020
Published online: 12 January 2021

Abstract

We developed a unique model for exciton in monolayer medium with an effective dielectric constant ${ϵ}_{\mathit{eff}}$ (in which the monolayer material is placed on a substrate such as fused silica glass or $Si{O}_2$ in experiments). Our model was based on an exact solution of the corresponding fully-covariant two-body Dirac-Coulomb type equation. For singlet quantum state of a static electron-hole pair in such a medium, we obtained a non-perturbative frequency spectrum composed of real and imaginary parts. We obtained explicit expressions for practical calculations of binding energy and decaytime of such a system. The results show that one can actively tune both binding energy and decaytime of an exciton during photo-excitation experiments by adjusting the value of ${ϵ}_{\mathit{eff}}$. We think that our calculations and approaches eliminate cross-talk in the literature and explain the discrepancy between experimental results of binding energy of an exciton for different substrates.