Exciton-Polariton Engineering through Spin Dynamics in Two-Dimensional Van der Waals Heterostructures

The influence of spin on the excitonic properties of Van der Waals (vdW) magnetic heterostructures positions these systems as compelling ingredients for exploring correlations between magnetic phenomena and light in hybrid light-matter quasiparticles, or exciton-polaritons. Magnetic proximity effects in vdW heterostructures have been used to selectively tune the response of valley excitons and to induce zero-field energy splitting of normally degenerate valleys [1-3]. However, translating these proximity induced spin-exciton interactions to polaritons remains unexplored. In this study, we investigate the strong-coupling between photons and spin-correlated excitons in 2D vdW magnetic heterostructures made from transition metal dichalcogenides. Utilizing a WSe₂/CrI₃ heterostructure embedded in an optical microcavity, we observe exciton-polariton dispersions that are influenced by the spin alignment of CrI₃. Zero-field circularly polarized reflectivity measurements demonstrate the tunability of dispersion energies and linewidths based on the spin orientation of CrI₃. Polarized emission further confirms the influence of CrI₃ on valley polarization and the energetic characteristics of polaritons, underscoring the potential of vdW magnetic heterostructures for leveraging spin ordering as a mechanism for controlling light-matter hybrids.



[1] Zhong, Sci. Adv. 3, 1603113 (2017)

[2] Seyler, Nano Lett. 18, 3823−3828 (2018)

[3] Mukherjee, Nat. Commun. 11, 5502 (2020)