Electrostatic control of the trion fine structure in transition metal dichalcogenide monolayers

TL;DR

This paper investigates how electrostatic tuning affects the fine structure of trions in transition metal dichalcogenide monolayers, revealing control over optical properties through doping and dielectric environment adjustments.

Contribution

It provides a detailed analysis of the trion fine structure and demonstrates electrostatic control mechanisms in TMDC monolayers using a three-body Hamiltonian approach.

Findings

Trion fine structure is influenced by spin-valley interactions and exchange effects.

Doping and dielectric environment variations can tune trion energy levels.

Anti-crossing of bright and dark states impacts optical spectra.

Abstract

Charged excitons (trions) are essential for the optical spectra in low dimensional doped monolayers (ML) of transitional metal dichalcogenides (TMDC). Using a direct diagonalization of the three-body Hamiltonian, we explore the low-lying trion states in four types of TMDC MLs. We show that the trions fine structure results from the interplay between the spin-valley fine structure of the single-particle bands and the exchange interaction between the composing particles. We demonstrate that by variations of the doping and dielectric environment, trion energy fine structure can be tuned, leading to anti-crossing of the bright and dark states with substantial implications for the optical spectra of TMDC MLs.