Excitons are fundamental excitations that govern the optical properties of semiconductors. Interacting excitons can lead to various emergent phases of matter and large nonlinear optical responses. In most semiconductors, excitons interact via exchange interaction or phase space filling. Correlated materials that host excitons coupled to other degrees of freedom offer hitherto unexplored pathways for controlling these interactions. Here, we demonstrate magnon-mediated excitonic interactions in CrSBr, an antiferromagnetic semiconductor. This interaction manifests as the dependence of exciton energy on exciton density via a magnonic adjustment of the spin canting angle. Our study demonstrates the emergence of quasiparticle-mediated interactions in correlated quantum materials, leading to large nonlinear optical responses and potential device concepts such as magnon-mediated quantum transducers.
@article{arxiv.2409.18501,
title = {Magnon-mediated exciton-exciton interaction in a van der Waals antiferromagnet},
author = {Biswajit Datta and Pratap Chandra Adak and Sichao Yu and Agneya V. Dharmapalan and Siedah J. Hall and Anton Vakulenko and Filipp Komissarenko and Egor Kurganov and Jiamin Quan and Wei Wang and Kseniia Mosina and Zdeněk Sofer and Dimitar Pashov and Mark van Schilfgaarde and Swagata Acharya and Akashdeep Kamra and Matthew Y. Sfeir and Andrea Alù and Alexander B. Khanikaev and Vinod M. Menon},
journal= {arXiv preprint arXiv:2409.18501},
year = {2025}
}