Emergent chiral excitons correlated with spin textures in the van der Waals ferromagnet CrBr<sub>3</sub>
ORAL
Abstract
Emergent magnetism in two-dimensional van der Waals crystals can stabilize optical quasiparticles through exchange coupling to real-space spin order. We show that CrBr3 hosts an exciton whose presence and chirality depend on nonuniform spin textures. Polarization-resolved absorption with circular light at 1.5 K (well below TC ≈ 37 K), reveals strong circular dichroism that is tunable by both the direction and magnitude of an external magnetic field. The exciton intensity grows at low out-of-plane fields, reaches a maximum at an intermediate field, and is quenched when the field drives uniform spin alignment. Magnetic force microscopy maps the evolution of the spin texture, and its field dependence closely mirrors the exciton response. These results establish a connection between real-space spin textures and chiral excitons and suggest a route to field-addressable chiral optical states in 2D magnets.
*This work was supported by the National Research Foundation of Korea (NRF) (Grant Nos. 2021R1A2C3004989 and 2017R1A5A1014862) and by the Institute for Basic Science (IBS-R036-Y1). B.C.P. acknowledges support from the Institute for Basic Science (IBS-R036-D1). M.K. was supported by the Ministry of Education, Singapore, through the Research Centres of Excellence program (EDUNC-33-18-279-V12, I-FIM), by the Ministry of Education Academic Research Fund Tier 2 (MOE-T2EP50122-0012), and by the Air Force Office of Scientific Research and the Office of Naval Research Global under award FA8655-21-1-7026. Y.-W.S. was supported by a KIAS Individual Grant (CG031509).
–
Publication:J. Kim et al., "Spin texture–stabilized chiral excitons in a van der Waals ferromagnet," manuscript under review, 2025.
