2025/03/27 by Zhizi Guan, Zhiwei Peng, Guan, Zhizi +7
Engineering · Materials Science · Physics and Astronomy · #2D Materials and Applications #FOS: Physical sciences #Optics (physics.optics) #Plasmonic and Surface Plasmon Research #Strong Light-Matter Interactions
paper · pdf · doi:10.48550/arxiv.2503.21238
openalex publication_date 2025/03/27 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Symmetry governs the selection rules of light-matter interactions in crystalline materials, making symmetry manipulation a powerful tool for tuning their optical properties. Here, we demonstrate that the hot-electron injection from a plasmonic resonator breaks the centrosymmtry of an adjacent transition metal dichalcogenide bilayer, probed via second-harmonic generation (SHG) in a Au-nanoparticle@bilayer-MoS2@Au-film hybrid system. Power-dependent SHG measurements exhibit saturation behavior, consistent with a capacitor model where interfacial charge accumulation creates a dynamic barrier limiting further electron injection. Polarization-resolved SHG measurements reveal anisotropic second-order susceptibility response under hot-electron injection, where the contrast between different susceptibility components provides a quantitative measure of symmetry-breaking anisotropy. First-principles calculations elucidate the nonlinear optical responses evolution in bilayer MoS2 and comfirm the anisotropic modification of susceptibility components under hot-electron injection, modeled by a perpendicular electric field. Our work establishes SHG as an effective probe of hot-electron-induced symmetry breaking in 2D materials, demonstrating a promising approach for ultrafast manipulation of material properties through controlled charge injection at the nanoscale.