  Morphological control at the nanoscale paves the way to fabricate
nanostructures with desired plasmonic properties. We report the nanoengineering
of plasmon resonances in 1D hollow nanostructures of two different AuAg
nanotubes; completely hollow nanotubes and hybrid nanotubes comprising solid Ag
and hollow AuAg segments. Spatially resolved plasmon mapping by electron energy
loss spectroscopy (EELS) revealed the presence of high order resonator-like
modes and localized surface plasmon resonance (LSPR) modes in both nanotubes.
Experimental findings are accurately correlated with boundary element method
(BEM) simulations, where both experiments and simulations revealed that the
plasmon resonances are intensely present inside the nanotubes due to plasmon
hybridization. Based on the experimental and simulated results reported, we
show that the novel hybrid AuAg nanotubes possess two significant coexisting
features: (i) LSPRs have been generated distinctively from the hollow and solid
parts of the hybrid AuAg nanotube, which opens the way to control a broad range
of plasmon resonances with one single nanostructure and (ii) the periodicity of
the high-order modes are disrupted due to the plasmon hybridization by the
interaction of solid and hollow parts, resulting in an asymmetrical plasmon
distribution in 1D nanostructures. The asymmetry could be modulated/engineered
leading to control coded plasmonic nanotubes.
