Magneto-optics in a van der Waals magnet tuned by self-hybridized polaritons

Controlling quantum materials with light is of fundamental and technological importance. By utilizing the strong coupling of light and matter in optical cavities1-3, recent studies were able to modify some of their most defining features4-6. Here we study the magneto-optical properties of a van der Waals magnet that supports strong coupling of photons and excitons even in the absence of external cavity mirrors. In this material-the layered magnetic semiconductor CrSBr-emergent light-matter hybrids called polaritons are shown to substantially increase the spectral bandwidth of correlations between the magnetic, electronic and optical properties, enabling largely tunable optical responses to applied magnetic fields and magnons. Our results highlight the importance of exciton-photon self-hybridization in van der Waals magnets and motivate novel directions for the manipulation of quantum material properties by strong light-matter coupling. In the layered magnetic semiconductor CrSBr, emergent light-matter hybrids (polaritons) increase the spectral bandwidth of correlations between the magnetic, electronic and optical properties, enabling largely tunable optical responses to applied magnetic fields and magnons.

Automated summary

By utilizing the strong coupling of light and matter in optical cavities, researchers have found that the optical properties of quantum materials can be controlled even without external cavity mirrors. In the layered magnetic semiconductor CrSBr, emergent light-matter hybrids called polaritons substantially increase the spectral bandwidth of correlations between magnetic, electronic, and optical properties, leading to largely tunable optical responses to applied magnetic fields and magnons. These findings highlight the importance of exciton-photon self-hybridization in van der Waals magnets and motivate new directions for manipulating quantum material properties through strong light-matter coupling.