Thermal phonon engineering by tailored nanostructures

Phonon engineering is expected to contribute to further development of various fields and technologies such as electronics, photonics, thermal engineering, and materials science. Although phonons inherently exist in condensed matter, their behavior strongly depends on the scale of the system and the materials, and they play a major role in electrical, optical, thermal, and mechanical properties. Therefore, researchers have been attempting to find effective ways to control phonons to modify the material properties-in this regard, nanostructuring was found to be highly effective. Here, we review recent advances in the simulations and experiments on phonon transport and thermal conduction control in nanostructures. We mainly focus on tailored nanostructures, especially phononic crystals of which the design is based on the nanoscale phonon transport property. (C) 2018 The Japan Society of Applied Physics