2019 journal article

On the importance of using exact full phonon dispersions for predicting interfacial thermal conductance of layered materials using diffuse mismatch model

AIP Advances.

Jun Liu

Source: ORCID
Added: December 30, 2019

Several models have been employed in the past to estimate interfacial thermal conductance (ITC) for different material interfaces, of which the diffuse mismatch model (DMM) has been generally accepted as reliable for rough material interfaces at high temperature. Even though the DMM has been shown to predict the correct order of magnitude in isotropic material interfaces, it is unable to reproduce the same accuracy for low-dimensional anisotropic layered materials, which have many potential applications. Furthermore, the use of approximated dispersion curves tends to overestimate the ITC. In this work, we propose a new method that utilizes a mode-to-mode comparison within the DMM framework to predict ITC. We employed this model to calculate ITC between layered materials such as MoS2 and graphite and metals such as Al, Au, and Cr. We then compared our values with previous literature data that employ linear dispersion relations and experimental data from time-domain thermoreflectance measurements. This new framework was then used to visualize the phonon focusing effect in anisotropic materials. Further analysis revealed that counting only the three acoustic modes and neglecting the low-frequency optical modes lead to significant underestimation of the ITC using DMM. Our findings indicate that it is imperative to use the exact full phonon dispersion relations in evaluating the ITC for low-dimensional layered materials.