Abstract
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.
Highlights
Low-dimensional layered materials such as few-layer graphene,1–4 graphite,5,6 black phosphorus,7–9 and transition metal dichalcogenides (TMDs)10–14 have garnered substantial interest in recent years
We aim to improve upon these models by incorporating the exact full phonon dispersion without approximation into the Diffuse Mismatch Model (DMM) to accurately predict the interfacial thermal conductance within the DMM framework
The frequency and group velocity of each mode are fed into our DMM code that calculates the interfacial thermal conductance
Summary
Low-dimensional layered materials such as few-layer graphene, graphite, black phosphorus, and transition metal dichalcogenides (TMDs) have garnered substantial interest in recent years. By utilizing the exact dispersion of acoustic phonons to calculate thermal conductance between metal-metal and metal-semiconductor interfaces, the DMM yielded results that varied significantly from the Debye approximation.24 For layered materials such as graphite, an isotropic phonon dispersion predicts thermal conductance with a high factor of error around 6.25 A general framework was recently proposed which used an anisotropic Debye dispersion to predict thermal conductance in graphite, Bi2Te3, and high-density polyethylene.. For layered materials such as graphite, an isotropic phonon dispersion predicts thermal conductance with a high factor of error around 6.25 A general framework was recently proposed which used an anisotropic Debye dispersion to predict thermal conductance in graphite, Bi2Te3, and high-density polyethylene.26 This was a significant improvement on the inaccurate isotropic model, which yielded results much closer to experimental values. We aim to improve upon these models by incorporating the exact full phonon dispersion without approximation into the DMM to accurately predict the interfacial thermal conductance within the DMM framework
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