  We present a review of the phonon thermal conductivity of segmented nanowires
focusing on theoretical results for Si and Si/Ge structures with the constant
and periodically modulated cross-sections. We describe the use of the
face-centered cubic cell and Born-von Karman models of the lattice vibrations
for calculating the phonon energy spectra in the segmented nanowires.
Modification of the phonon spectrum in such nanostructures results in strong
reduction of the phonon thermal conductivity and suppression of heat transfer
due to a trapping of phonon modes in nanowire segments. Possible practical
applications of segmented nanowires in thermoelectric energy generation are
also discussed.
