# Magneto-Excitonic Duality From Monolayer to Trilayer CrSBr

## TL;DR

This study reveals that monolayer to trilayer CrSBr exhibits dual excitonic behavior, supporting both Frenkel- and Wannier-Mott-like excitons, with robust magneto-excitonic coupling across layers, advancing understanding of 2D magnetic materials.

## Contribution

It demonstrates the coexistence of different excitonic types in CrSBr layers and explores their magnetic and optical properties, revealing layer-dependent excitonic signatures.

## Key findings

- CrSBr supports both Frenkel- and Wannier-Mott-like excitons.
- Magneto-excitonic coupling remains robust in few-layer CrSBr.
- Distinct excitonic responses observed in mono-, bi-, and trilayer samples.

## Abstract

Two-dimensional (2D) layered magnetic materials (LMMs) are a newly emerging class of van der Waals materials, opening new opportunities to study magneto-excitonic coupling. The air-stable, structurally and optically anisotropic A-type antiferromagnetic chromium sulfur bromide (CrSBr) is one of the most prominent examples of such LMMs. We investigate photoluminescence (PL) and PL excitation of mono- to tri-layers CrSBr and find that it exhibits a unique duplexity, supporting both Frenkel- and Wannier-Mott-like excitons. Our magneto-optical experiments reveal a similar excitonic response from the mono- and trilayer systems and a completely different signature in the bilayer flake. This shows a different origin of the low-lying excitonic species (A, A', and B) in the band structure. We confirm the robustness of the magneto-excitonic coupling in few-layer CrSBr. Our work enables a more comprehensive exploration of the dual excitonic behavior in 2D materials.