Plasmonic Field-Enhanced Zeeman Splitting in Ag-CsPbBr₃ Hybrid Nanostructures: A Step toward Tunable Magneto-Optical Devices

We present a systematic study of plasmon-enhanced magneto-optical (MO) effects in hybrid nanostructures composed of CsPbBr₃ nanocrystals (NCs) coupled with silver (Ag) nanoparticles (NPs). By harnessing the intense local electric fields generated via localized surface plasmon resonance (LSPR) of Ag NPs, we observe a marked enhancement in Zeeman splitting and magnetic circular dichroism (MCD) response near the band-edge transitions of the perovskite NCs. Three different configurations─uniformly distributed Ag NPs, clustered NPs, and physical mixtures─were employed to probe the influence of spatial arrangement on exciton-plasmon interactions. Among these, the uniform heterostructure exhibited the highest MO enhancement, attributed to optimal spectral and spatial overlap between excitonic and plasmonic modes. The Zeeman energy showed a linear dependence on magnetic field strength across all systems, with the strongest splitting observed in the uniform configuration. This work highlights the effectiveness of LSPR-driven field amplification in tuning spin-resolved optical transitions and establishes hybrid plasmonic-perovskite systems as promising candidates for future applications in magneto-optical sensing, spintronics, and quantum nanophononics.