Size effect on phonon hydrodynamics in graphite microstructures and nanostructures

Article

关键词: BOLTZMANN TRANSPORT-EQUATION;    THERMAL-CONDUCTIVITY;    HEAT-CONDUCTION;    DISPERSION;    SCATTERING;    GRAPHENE;    MODEL;   

DOI  :  10.1103/PhysRevB.104.075450

来源: SCIE

【 摘 要 】

The understanding of hydrodynamic heat transport in finite-sized graphitic materials remains elusive due to the lack of an efficient methodology. In this paper, we develop a computational framework enabling an accurate description of heat transport in anisotropic graphite ribbons by a kinetic theory approach with full quantum mechanical first-principles input. A unified analysis of the size scaling of the thermal conductivity in the longitudinal and transverse directions of the system is made within the computational framework complemented with a macroscopic hydrodynamic approach. As a result, we demonstrate a strong end effect on the phonon Knudsen minimum, as a hallmark of the transition from ballistic to hydrodynamic heat transports, along a rectangular graphite ribbon with finite length and width. The phonon Knudsen minimum is found to take place only when the ribbon length is similar to 5-10 times the upper limit of the width range in the hydrodynamic regime. This paper contributes to a unique methodology with high efficiency and a deeper understanding of the size effect on phonon hydrodynamics, which would open opportunities for its theoretical and experimental investigation in graphitic micro- and nanostructures.

【 授权许可】

Free