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

Exciton Polaritons in Emergent Two-Dimensional Semiconductors

“…For example, valley polarization, − valley coherence, , valley Hall effect, valley Stark effect, and Zeeman effect of TMD exciton polaritons have been extensively investigated. Recently, the nonlinear properties of such exciton polaritons have been also reported such as nonlinear bosonic interactions, − parametric scattering, , and polariton lasing. , Moreover, when the 2D excitons are hosted in 2DPK and 2D AFM semiconductors, exciton polaritons exhibit distinct control DOFs via the anisotropic nature of crystals , and strong magnetic responses. , Meanwhile, explorations of distinct optical resonators have been going beyond the traditional configurations of FP cavities and PC, extending to extreme nanophotonics of plasmonic nanocavities ,− and deliberately designed PCs with nontrivial topological photonic bands. ,,− ,− Along with the advancements of distinct photonic designs and nanofabrication techniques, these distinct optical resonators unveil fascinating photonic behaviors in the strong coupling regime, especially for 2D exciton polaritons. For example, optical resonators of plasmonic nanocavities can even realize the strong coupling at single molecule level at room temperature by leveraging advantages of nanometer-sized mode volume .…”

“…In addition, these exciton polaritons have demonstrated strong anisotropic features following their exciton fraction. As the energy of excitons varies from AFM to FM orders, the exciton polaritons can be largely detuned by applying appropriate external magnetic fields, leading to controllable contributions from excitons and photons. , Specifically, the interaction between excitons and magnons influences the exciton resonances’ shifts as a function of magnetic moment angle between adjacent layers, leading to cosine-function-like shifts in exciton resonances and polariton states (Figure e) . Moreover, magnons, quantum excitations of spin waves, can also efficiently coupled with exciton polaritons in CrSBr inherited from their exciton constituent under external magnetic field .…”

“…60 Moreover, magnons, quantum excitations of spin waves, can also efficiently coupled with exciton polaritons in CrSBr inherited from their exciton constituent under external magnetic field. 59 For the AFM semiconductor of NiPS 3 , the strong coupling between photons and spin-correlated excitons in a FP cavity generates distinct exciton polaritons that inherit characteristics of excitons, photons, and spins (Figure 6f). 58 Because the spin-correlated excitons cannot efficiently couple with phonons at low temperatures, most phonons cannot facilitate relaxation of polarized excitons to the lower polaritons and lead to polariton bottleneck relaxation and dominant PL emissions around the uncoupled exciton resonance.…”

Ferromagnetic Interlayer Coupling in CrSBr Crystals Irradiated by Ions

“…Due to the pronounced correlations between magnons, photons, electrons, and phonons, ,− CrSBr is emerging as one of the most promising materials for such applications. Up to the Néel temperature of T N = 132 ± 1 K, the FM spin order within each layer is compensated by an AFM arrangement of the vdW layers in the out-of-plane direction ( c -axis), which is the reason for the vanishing net magnetization of pristine bulk crystals.…”

Charge Transfer and Asymmetric Coupling of MoSe2 Valleys to the Magnetic Order of CrSBr

“…In Figure (d), the PL spectrum of CrSBr at 3.6 K is displayed in the left part. Several PL peaks are observed below 1.4 eV and associated with excitons, ,,, defects, and strong exciton–photon coupling…”