Extended Multi-Temperature Model for Electron--Phonon Coupling and Ultrafast Thermal Transport in Graphene

TL;DR

This paper introduces an extended multi-temperature model for ultrafast thermal transport in graphene, capturing non-diffusive and non-local effects to better understand electron-phonon interactions and heat flow in low-dimensional materials.

Contribution

The authors develop a comprehensive multi-temperature framework that incorporates non-diffusive phenomena and benchmarks it against Boltzmann transport, advancing the modeling of thermal dynamics in graphene.

Findings

Enhanced model accurately captures branch-dependent energy relaxation.

Identifies bottlenecks in thermalization processes.

Provides insights into phonon dynamics and electron-phonon interactions.

Abstract

Ultrafast thermal transport in low-dimensional materials challenges traditional diffusive models due to reduced scattering, strong electron-phonon coupling, and pronounced non-equilibrium effects. To address these complexities, we extend the macroscopic multi-temperature model by incorporating non-diffusive and non-local phenomena, treating electrons, optical phonons, and acoustic phonons as coupled but thermally distinct subsystems. We benchmark this enhanced framework against the multi-temperature Boltzmann transport equation, enabling detailed resolution of branch-dependent energy relaxation and identifying bottlenecks in thermalization. This approach provides a more accurate and comprehensive description of heat flow in emerging materials, offering novel insights into phonon dynamics and electron-phonon interactions. These theoretical advances pave the way for the improved design and optimization of next-generation nanoelectronic and photothermal devices.