[17a-WL2_201-1~11] 3.11 Nanoscale optical science and near-field optics

11:45 AM - 12:00 PM JST(2:45 AM - 3:00 AM UTC)

[17a-WL2_201-11] [The 59th Young Scientist Presentation Award Speech] Plasmonic properties of PtSn nanoparticles with a B8₁-type anisotropic crystal structure

〇HYUNJI LEE¹, Haruka Takekuma^1,2, Ryota Sato², Kenji Iida³, Toshiharu Teranishi^1,2 (1.Kyoto Univ., 2.ICR, Kyoto Univ., 3.ICAT, Hokkaido Univ.)

Keywords:

Localized surface plasmon resonance,Anisotropic crystal structure,Intermetallic nanoparticle

Localized surface plasmon resonance (LSPR) is a foundamental phenomenon utilized across a wide range of fields. While previous studies have predominantly focused on nanoparticles (NPs) with isotropic crystal structures—such as face-centered cubic (fcc; Au, Ag, Cu) or C1 (CaF₂-type) structures —this study shifts attention to the influence of anisotropic crystal structures on plasmonic properties. In this research, we investigate spherical intermetallic PtSn NPs with an anisotropic B8₁ (NiAs-type) structure. Despite their spherical morphology, these PtSn NPs exhibit two distinct LSPR peaks at approximately 380 nm (visible region) and 850 nm (NIR region). To elucidate the origin of this unusual dual-peak behavior, quantitative quantum chemical calculations and spectroscopic ellipsometry measurements of bulk PtSn were performed. The results clearly demonstrate that the dual LSPR peaks do not arise from particle shape effects but the intrinsic anisotropy of the crystal structure. These findings highlights lattice symmetry as a critical factor in determining the optical properties of plasmonic NPs.