Excitons, trions, and biexcitons in transition metal dichalcogenides: magnetic field dependence

TL;DR

This paper investigates how a perpendicular magnetic field affects the binding energies and structures of excitons, trions, and biexcitons in monolayer transition metal dichalcogenides using advanced computational methods and compares results with experimental data.

Contribution

It introduces a simplified variational approach supporting the stochastic variational method for excitons and explores the impact of local potential fluctuations on excitonic binding energies.

Findings

Magnetic field influences exciton, trion, and biexciton binding energies.

Local potential fluctuations significantly increase binding energies.

The exciton diamagnetic shift aligns with recent experimental observations.

Abstract

The influence of a perpendicular magnetic field on the binding energy and structural properties of excitons, trions, and biexcitons in monolayers of semiconducting transition metal dichalcogenides (TMDs) is investigated. The stochastic variational method (SVM) with a correlated Gaussian basis is used to calculate the different properties of these few-particle systems. In addition, we present a simplified variational approach which supports the SVM results for excitons as a function of magnetic field. The exciton diamagnetic shift is compared with recent experimental results and we extend this concept to trions and biexcitons. The effect of a local potential fluctuation, which we model by a circular potential well, on the binding energy of trions and biexcitons is investigated and found to significantly increase the binding of those excitonic complexes.