Nanorod Size Dependence of Coherent Coupling between Individual and Collective Excitations via Transverse Electromagnetic Field

Plasmon is a collective excitation in metals formed through the Coulomb interaction between individual excitations of electron-hole pairs. In many previous studies on the plasmonic response, the role of the longitudinal field has been focused almost exclusively on the light-induced plasmonic phenomena, e.g., hot-carrier generation. In our previous study [Phys. Rev. B 105, 165408 (2022)], we have revealed the significant contribution of the transverse electromagnetic field to connect plasmons and electron-hole pairs in nanostructures based on the self-consistent and nonlocal response theory. In this study, we examine how this contribution appears depending on the system parameters, e.g., length and refractive index. The elucidation of roles of coherent coupling between the collective and individual excitations by the transverse field will lead to the principle of controlling bidirectional energy transfer between the plasmons and electron-hole pairs, which could significantly enhance hot-carrier generation efficiency.