Orthogonal tight-binding model for the thermal conductivity of Si

Abstract

Predictive modeling of the thermal conductivity of nanostructures remains a large challenge. Ab initio studies rely on parametrized models of scattering rates of the nanostructure elements. Simplified interatomic potentials, on the other hand, often fail in the quantitative prediction of thermal conductivity. We have developed a simple and short-ranged orthogonal tight-binding model for the thermal properties of Si. We systematically introduce separate handles to tune the value and slope of the potential energy with respect to interatomic distance. Furthermore, we add an embedding potential in our model to capture the correct structural stability trend in Si. The model shows excellent transferability to the thermal properties of diamond Si along with good reproduction of the relative stabilities of different structures. We demonstrate the improvement over earlier tight-binding models and contrast the transferability of our model with simple interatomic potentials.