  Phonons - quanta of crystal lattice vibrations - reveal themselves in all
electrical, thermal and optical phenomena in materials. Nanostructures open
exciting opportunities for tuning the phonon energy spectrum and related
properties of materials for specific applications. The possibilities for
controlled modification of the phonon transport and phonon interactions -
referred to as phonon engineering or phononics - increase even further with the
advent of graphene and two-dimensional van der Waals materials. We describe
methods for tuning the phonon spectrum and controlling the thermal properties
of the low-dimensional materials via ribbon edges, grain boundaries, isotope
composition, defect concentration, and atomic-plane orientation.
