Self-hybridized polaritons in an anisotropic magnetic material

Recent discoveries of van der Waals magnetic materials offer novel opportunities for exploring magnetic order in reduced dimensions, with implications for quantum phenomena and device applications. CrSBr, an antiferromagnetic semiconductor, exhibits robust magnetically correlated excitons and supports strong light-matter interaction owing to its high binding energy along with large oscillator strength. Our study focuses on self-hybridized polaritons in CrSBr, utilizing its high refractive index for strong light confinement without external mirrors. We employ polarization-resolved photoluminescence excitation spectroscopy to probe the anisotropic properties of CrSBr. The strong dependency of photoluminescence (PL) anisotropy on the excitation energy reveals insights into the underlying electronic structure and relaxation pathways. Furthermore, PL anisotropy depends on the Hopfield coefficients, i.e., the extent of admixture of photons and excitons, indicating a rich interplay between material and optical anisotropy. While our findings deepen the understanding of light-matter coupling in magnetic materials, they also bear significance for developing polarization-sensitive optoelectronic devices.

The work is supported by ARO (W911NF-22-1-0091) and NSF (OMA-2328993).