Generalized two-temperature model for coupled phonons

TL;DR

This paper extends the two-temperature model to coupled phonon groups in graphene, introducing new parameters to quantify phonon interactions and explaining thermal resistance phenomena.

Contribution

The study introduces a generalized two-temperature model with new physical quantities for phonon coupling, revealing size-dependent coupling length in graphene.

Findings

Quantifies phonon-phonon coupling with new factors

Explains thermal resistance in graphene

Shows coupling length depends on system size

Abstract

The design of graphene-based composite with high thermal conductivity requires a comprehensive understanding of phonon coupling in graphene. We extended the two-temperature model to coupled groups of phonon. The study give new physical quantities, the phonon-phonon coupling factor and length, to characterize the couplings quantitatively. Besides, our proposed coupling length has an obvious dependence on system size. Our studies can not only observe the nonequilibrium between different groups of phonon, but explain theoretically the thermal resistance inside graphene.