Parametrization of Density Functional Tight-Binding Method for Thermal Transport in Bulk and Low-Dimensional Si Systems

Understanding the thermal transport in different Si-based materials is of both practical and academic importance because of the essential role of such materials in modern electronic and microelectromechanical applications and other areas. Conventional atomic modeling approaches such as density functional theory offer high accuracy but can hardly handle a large system, whereas the empirical potentials used in classical molecular dynamics often lack accuracy or transferability. We have thus developed a new parametrization of the Si-Si interaction of the density-functional-based tight-binding method for the atomic scale investigation of thermal transport properties in various Si systems. We found that this parametrization can accurately predict many harmonic and anharmonic thermal transport properties in different silicon systems such as single-crystalline silicon, silicene, and silicene nanoribbons, showing excellent computational efficiency and transferability. Therefore, this Si Si parameter set can contribute to the fundamental understanding of thermal transport in various complex Si-based systems that are difficult to model accurately using traditional methods.