Nonlocal and quantum mechanical phenomena in noble metal nanostructures
become increasingly crucial when the relevant length scales in hybrid
nanostructures reach the few-nanometer regime. In practice, such mesoscopic
effects at metal-dielectric interfaces can be described using exemplary
surface-response functions (SRFs) embodied by the Feibelman d-parameters.
Here we show that SRFs dramatically influence quantum electrodynamic phenomena
-- such as the Purcell enhancement and Lamb shift -- for quantum emitters close
to a diverse range of noble metal nanostructures interfacing different
homogeneous media. Dielectric environments with higher permittivities are shown
to increase the magnitude of SRFs calculated within the specular-reflection
model. In parallel, the role of SRFs is enhanced in nanostructures
characterized by large surface-to-volume ratios, such as thin planar metallic
films or shells of core-shell nanoparticles. By investigating emitter quantum
dynamics close to such plasmonic architectures, we show that decreasing the
width of the metal region, or increasing the permittivity of the interfacing
dielectric, leads to a significant change in the Purcell enhancement, Lamb
shift, and visible far-field spontaneous emission spectrum, as an immediate
consequence of SRFs. We anticipate that fitting the theoretically modelled
spectra to experiments could allow for experimental determination of the
d-parameters.Comment: 9 pages, 5 figure