Excitons and trions in CrSBr bilayers

TL;DR

This paper provides a theoretical analysis of excitons and trions in CrSBr bilayers, exploring their binding energies, light interactions, and effects of various parameters, aligning well with recent experimental findings.

Contribution

It introduces a comprehensive theoretical model for excitons and trions in CrSBr bilayers, considering anisotropic dispersion and interlayer effects, which was not previously detailed.

Findings

Calculated exciton and trion binding energies match experimental data.

Analyzed effects of dielectric screening and interlayer distance on excitonic properties.

Explored exciton-light interactions including radiative decay and exchange effects.

Abstract

We study theoretically the neutral and charged excitons in two-dimensional semiconductors with anisotropic dispersion of charge carriers. Such a situation is realized in CrSBr-based van der Waals heterostructures. We calculate the binding energies of excitons and trions and explore their dependence on the mass ratio, dielectric screening, and interlayer distance in bilayer structures. We also address the effects of exciton-light coupling, including the radiative decay and long-range electron-hole exchange interaction, and briefly analyze correlations between the excitons and the Fermi sea of resident electrons. The estimates for CrSBr bilayers are in reasonable agreement with recent experiments.