Lifetime of the first and second collective excitations in metallic nanoparticles

• Published in: Physical review. B, Condensed matter and materials physics Condensed matter and materials physics, 2005-09, Vol.72 (11), p.115410.1-115410.17, Article 115410
• Main Authors: WEICK, Guillaume, MOLINA, Rafael A, WEINMANN, Dietmar, JALABERT, Rodolfo A
• Format: Article
• Language: English
• Subjects: Condensed Matter; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Electronic structure of nanoscale materials : clusters, nanoparticles, nanotubes, and nanocrystals; Exact sciences and technology; Mesoscopic Systems and Quantum Hall Effect; Physics
• ISSN: 1098-0121; 1550-235X
• DOI: 10.1103/PhysRevB.72.115410

We determine the lifetime of the surface plasmon in metallic nanoparticles under various conditions, concentrating on the Landau damping, which is the dominant mechanism for intermediate-size particles. Besides the main contribution to the lifetime, which smoothly increases with the size of the particle, our semiclassical evaluation yields an additional oscillating component. For the case of noble metal particles embedded in a dielectric medium, it is crucial to consider the details of the electronic confinement; we show that in this case the lifetime is determined by the shape of the self-consistent potential near the surface. Strong enough perturbations may lead to the second collective excitation of the electronic system. We study its lifetime, which is limited by two decay channels: Landau damping and ionization. We determine the size dependence of both contributions and show that the second collective excitation remains as a well defined resonance.