Landau damping of quantum plasmons in metal nanostructures

Abstract

Using the random phase approximation with both real space and discrete electron-hole (e-h) pair basis sets, we study the broadening of surface plasmons in metal structures of reduced dimensionality, where Landau damping is the dominant dissipation channel and presents an intrinsic limitation to plasmonics technology. We show that for every prototypical class of systems considered, including zero-dimensional nanoshells, one-dimensional coaxial nanotubes and two-dimensional ultrathin films, Landau damping can be drastically tuned due to energy quantization of the individual electron levels and e-h pairs. Both the generic trend and oscillatory nature of the tunability are in stark contrast with the expectations of the semiclassical surface scattering picture. Our approach also allows to vividly depict the evolution of the plasmons from the quantum to the classical regime, and to elucidate the underlying physical origin of hybridization broadening of nearly degenerate plasmon modes. These findings may serve as a guide in the future design of plasmonic nanostructures of desirable functionalities.

A generalized non-local optical response theory for plasmonic nanostructures

“…Re-introducing the diffusion constant and 34 . In support of our prediction of diffusive broadening, recent RPA studies reveal an increased plasmon linewidth associated with Landau damping 35 , that is, electron-hole pair excitation near the surface of nanostructures as also observed in studies based on timedependent density functional theory (TD-DFT) 36 . We provide in the following two key examples of the GNOR approach, demonstrating that the interplay of quantum pressure and diffusion has a remarkable impact on the optical response of plasmonics nanostructures and solving long-standing open problems.…”

Harvesting the loss: surface plasmon-based hot electron photodetection

“…During nonradiative plasmon decay, hot electron-hole pairs are created through Landau damping on a time scale of femtoseconds [70]. Theoretical calculations of hot electron energy distribution in bulk metal, based on the electron density of states approximated by a free electron gas model, shows a broad continuous distribution of hot electron energies upon excitation [28] ( Figure 1B).…”

Solar-Powered Plasmon-Enhanced Heterogeneous Catalysis

“…The lifetime of plasmons is therefore determined by the dephasing time of this coherent oscillation, which typically falls in the 5-100 fs timescale [29]. Each plasmon can decay radiatively by the elastic re-emission of a photon (scattering) or non-radiatively through Landau damping [41], which, in turn, results in the generation of energetic hot electronhole pairs in the metal nanostructure ( Figure 1B). Eventually, hot carrier couples to phonon modes producing local heating of the metallic nanostructure.…”