Phonon weak couplings in nanoscale thermophysics

With the development of nanoscale thermophysics, a vast number of novel phenomena have emerged, which closely relate to phonon weak couplings. The causes of phonon weak couplings mechanism and related physical discoveries are discussed in this article, including the size effect of low-dimensional systems, multi-temperature model, and van der Waals cross interfaces. Corresponding frontier researches are also summarized. The current problems of phonon weak couplings, such as how to add phonon wave-like behaviors into the theoretical model, are also briefly discussed and prospected.