Resonance shifts and spill-out effects in self-consistent hydrodynamic nanoplasmonics

Abstract

The standard hydrodynamic Drude model with hard-wall boundary conditions can give accurate quantitative predictions for the optical response of noble-metal nanoparticles. However, it is less accurate for other metallic nanosystems, where surface effects due to electron density spill-out in free space cannot be neglected. Here we address the fundamental question whether the description of surface effects in plasmonics necessarily requires a fully quantum-mechanical approach, such as time-dependent density-functional theory (TD-DFT), that goes beyond an effective Drude-type model. We present a more general formulation of the hydrodynamic model for the inhomogeneous electron gas, which additionally includes gradients of the electron density in the energy functional. In doing so, we arrive at a Self-Consistent Hydrodynamic Model (SC-HDM), where spill-out emerges naturally. We find a redshift for the optical response of Na nanowires, and a blueshift for Ag nanowires, which are both in quantitative agreement with experiments and more advanced quantum methods. The SC-HDM gives accurate results with modest computational effort, and can be applied to arbitrary nanoplasmonic systems of much larger sizes than accessible with TD-DFT methods. Moreover, while the latter typically neglect retardation effects due to time-varying magnetic fields, our SC-HDM takes retardation fully into account.

27 pages, including 4 figures. Supplemental Material is available upon request to authors

References in corpus (5)

• Blueshift of the surface plasmon resonance in silver nanoparticles studied with EELS
• Surface plasmon in metallic nanoparticles: renormalization effects due to electron-hole excitations
• Laplacian-level kinetic energy approximations based on the fourth-order gradient expansion: Global assessment and application to the subsystem formulation of density functional theory
• Surface-enhanced Raman spectroscopy (SERS): nonlocal limitations
• Nonlocal effects: relevance for the spontaneous emission rates of quantum emitters coupled to plasmonic structures

Cited by in corpus (15)

• Size-dependent nonlocal effects in plasmonic semiconductor particles
• Full Hydrodynamic Model of Nonlinear Electromagnetic Response in Metallic Metamaterials
• Robustness of the Rabi splitting under nonlocal corrections in plexcitonics
• Plasmonic modes of polygonal particles calculated using a quantum hydrodynamics method
• Monitoring strong coupling in nonlocal plasmonics with electron spectroscopies
• Electromagnetic reflection, transmission and energy density at boundaries of nonlocal media
• Nonlocal effects in singular plasmonic metasurfaces
• Ab-initio approach for gap plasmonics
• Analysis of the interaction between classical and quantum plasmons via FDTD-TDDFT method
• Nonlocal effects in plasmonic metasurfaces with almost touching surfaces
• Plasmons in ultra-thin gold slabs with quantum spill-out: Fourier modal method, perturbative approach, and analytical model
• Nano-corrugation induced forces between electrically neutral plasmonic objects
• Viscoelastic optical nonlocality of low-loss epsilon-near-zero nanofilms
• Matters Arising: Modeling and observation of mid-infrared nonlocality in effective epsilon-near-zero ultranarrow coaxial apertures
• Second-harmonic generation due to coulomb-like interaction in a heterodimer of subwavelength dimensions