Phonon weak couplings model and its applications: A revisit to two-temperature non-equilibrium transport

The thermal management on low-dimensional materials requires a fundamental understanding of phonon couplings, which dominates thermal transport. In this mini-review, recent studies on weak couplings between phonon and other energy carriers are reviewed firstly. Then, a generalized analytical model, phonon weak couplings model, is proposed based on Boltzmann transport equation. When applying this model to describe recent works on weak couplings of phonons, it is classified as “implicit couplings” and “explicit couplings”, corresponding to couplings within a single structure and between two structures, respectively. Furthermore, perspectives and limitations of phonon weak couplings model are summarized, and potential research prospects are given to inspire future investigations and applications.