Prediction of thermal conductivity of diamond film by neural network based on first principles
Abstract
<p indent="0mm">As a high thermal conductivity material, diamond is significant for microelectronic cooling and other applications. Multiscale analysis of diamond’s thermal conductivity is beneficial to designing micro-nano electronic components and thermal management. The Boltzmann transport equation is an ideal tool to describe the phenomenon of multiscale phonon transport. However, due to its high dimensionality, it is incredibly challenging to use it to calculate and predict the thermal conductivity of diamonds at different scales. Based on the first principle, physical information neural network and Boltzmann transport equation, this paper effectively predicts the multiscale thermal transport of phonons in diamond and makes related analysis. After the phonon dispersion information, the diamond’s group velocity and scattering rate were calculated by the first principles. Relevant results were input into the physical information neural network as training samples. To introduce the Boltzmann transport equation as physical information in physical information neural network, we embedded related control equations and boundary conditions in the loss function of the neural network. When the loss function of the physical information neural network drops to a set standard, the trained model can accurately predict the phonon energy distribution. In this paper, physical information neural network was used to predict the transport law of phonons in a one-dimensional diamond film at different temperatures and scales. The solution results of the physical information neural network and linearized Boltzmann transport equation have high consistency. It could be deduced that the thermal conductivity of diamond had a size effect on the millimeter scale. At the same temperature, the smaller the scale, the lower the normalized thermal conductivity of the diamond, and the lower the temperature, the more pronounced the size effect is on the thermal conductivity. Under the same scale, the normalized thermal conductivity was lower, and the change law of the phonon thermal conductivity of each mode of the diamond was the same.</p>
