Orateur
Description
Van der Waals (vdW) materials have revolutionized our understanding of correlated quantum phenomena, where structural confinement and reduced screening give rise to strongly bound excitons and a wide variety of emergent electronic and magnetic phases. Among these, magnetic vdW semiconductors open an entirely new frontier where Coulomb correlations can be tuned in situ by the material’s intrinsic magnetic order. In this talk, I will focus on CrSBr, a semiconducting vdW magnet that uniquely combines robust magnetism with excitonic resonances. I will first discuss how spin-controlled quantum confinement of magnetic excitons in CrSBr can be manipulated by directly probing their internal Rydberg-like transitions. I will then show how terahertz polarization spectroscopy, combined with near-field microscopy, captures the formation and ultrafast relaxation dynamics of these excitons in the monolayer limit. Together, these results provide a direct view of the dielectric response of quasi-one-dimensional magnetic excitons and establish CrSBr as a model system for exploring magnetically controlled excitonic physics. In future applications, excitons or even condensates may be interfaced with spintronics, enabling on-demand phase transitions through extrinsically switchable Coulomb correlations.
