  Phonons diffraction and interference patterns are observed at the atomic
scale, using molecular dynamics simulations in systems containing crystalline
silicon and nanometric obstacles as voids or amorphous-inclusions. The
diffraction patterns caused by these nano-architectured systems of the same
order as the phonon wavelengths are similar to the ones predicted by a simple
Fresnel-Kirchhoff integral, with a few differences due to the nature of the
obstacle and the anisotropy of crystalline silicon. These findings give
evidence of the wave nature of phonons, can help to a better comprehension of
the interaction of phonons with nanoobjects and at long term can be useful for
intelligent thermal management and phonon frequency filtering at the nanoscale.
