Plasmon-enhanced phonon
losses. (a) Experimental (full curves)
and calculated (dashed curves) EELS spectra at one of the tips of
a metallic nanowire fully supported on h-BN (configuration
(2) in Figure 1a) for
different lengths of the nanowire: 1.6, 2.0, 2.1, and 2.9 μm.
When the dipolar plasmon mode is close to or on resonance with h-BN phonon modes, the latter are enhanced, leading to the
appearance of multiple peaks. (b,c) Spectra as a function of distance
from the nanowire tip for lengths 2.0 μm (b) and 2.9 μm
(c). The ZO, PPS, FKS, LO, PPA, and uncoupled plasmon (P) modes are
labeled as described in the main text. (d) Peak intensities retrieved
from fits to spectra at different distances from the nanowire tip
(data shown in SI Figure 13).