Exciton Transport in Van der Waals Antiferromagnet CrSBr

The recent discovery of <i>magnetic excitons</i> – a rare type of optical excitation that emerges from spin-polarized electronic states in magnets – raises important questions about elemental interactions between excitons, magnons, and light. The prototypical layered antiferromagnetic semiconductor CrSBr and its strongly bound excitons are an exceptional platform to address such questions. In this contribution, we present the results of a study of the spatial transport of this intriguing type of exciton with particular focus on the role of crystal anisotropy, magnons and the magnetic order. We demonstrate highly non-linear exciton transport with unusual temperature dependence that culminates in substantially enhanced exciton propagation at the antiferromagnet-to-paramagnet phase transition. Observations of anomalous and effectively negative transport further indicate the substantial coupling of excitonic, vibronic, and magnetic degrees of freedom.