ABSTRACT
Phonons, the quantized oscillations of a crystal lattice, have at-
tracted strong interest among physics and engineering communities
who study graphene. On the one hand, attention is paid to acoustic
phonons which are responsible for the heat transport in graphene at
room temperatures. On the other hand, optical phonons are utilized
in Raman experiments with few-layer graphene when counting the
number of atomic planes. Elucidation of the fundamental difference
between the phonon spectra, energy dispersion, and scattering
rates in 2D and 3D systems represents another subject of an
intensive research work. There is a remarkable distinction between
the phonons which exist in the 2D crystals on the one side and
the phonons existing in the 3D bulk crystals on the other side.
The former system is represented with graphene or with the
basal planes of graphite, while the latter case is related to the
most of the 3D solid-state crystals. In this chapter we consider
phonon transport in graphene which is subjected to unconventional
boundary conditions. We also address the roles of in-plane and
cross-plane phonon oscillations and discuss experiments which
measure the thermal conductivity. We will focus our attention on
defects introduced by various lattice imperfections like strains,
defects, and impurity atoms which influence the phonon transport
in graphene and in few-layer graphene by changing the thermal
conductivity of those systems.