Anisotropy Effects on the Plasmonic Response of Nanoparticle Dimers.
We present an ab initio study of the anisotropy and atomic relaxation effects on the optical properties of nanoparticle dimers. Special emphasis is placed on the hybridization process of localized surface plasmons, plasmon-mediated photoinduced currents, and electric-field enhancement in the dimer junction. We show that there is a critical range of separations between the clusters (0.1-0.5 nm) in which the detailed atomic structure in the junction and the relative orientation of the nanoparticles have to be considered to obtain quantitative predictions for realistic nanoplasmonic devices. It is worth noting that this regime is characterized by the emergence of electron tunneling as a response to the driven electromagnetic field. The orientation of the particles not only modifies the attainable electric field enhancement but can lead to qualitative changes in the optical absorption spectrum of the system.
†Nano-Bio Spectroscopy group, Universidad del País Vasco UPV/EHU, CFM CSIC-UPV/EHU-MPC and DIPC, Avenida de Tolosa 72, E-20018 Donostia/San Sebastián, Spain.|‡ETSF Scientific Development Centre, Avenida de Tolosa 72, E-20018 Donostia/San Sebastián, Spain.
Alejandro
A
Varas
‡ETSF Scientific Development Centre, Avenida de Tolosa 72, E-20018 Donostia/San Sebastián, Spain.|¶Departamento de Física Teórica de la Materia Condensada and Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, E-28049 Cantoblanco, Madrid, Spain.
Pablo
P
García-González
¶Departamento de Física Teórica de la Materia Condensada and Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, E-28049 Cantoblanco, Madrid, Spain.
F J
FJ
García-Vidal
†Nano-Bio Spectroscopy group, Universidad del País Vasco UPV/EHU, CFM CSIC-UPV/EHU-MPC and DIPC, Avenida de Tolosa 72, E-20018 Donostia/San Sebastián, Spain.|‡ETSF Scientific Development Centre, Avenida de Tolosa 72, E-20018 Donostia/San Sebastián, Spain.|§Max Planck Institute for the Structure and Dynamics of Matter and Center for Free-Electron Laser Science and Department of Physics, Luruper Chaussee 149, 22761 Hamburg, Germany.
Angel
A
Rubio
ab-initio methods; charge-transfer modes; nanoparticle dimer; photoinduced tunneling; quantum plasmonics; surface-plasmon hybridization