Thermal conductivity of semimetallic materials from first principles*

Heat dissipation is an increasingly important issue in the design of new generations of electronic and optoelectronic devices. In this context, new high thermal conductivity materials are highly desirable to reduce the power density of hot spots in ultra-scaled transistors. Recently, a first principle study has found that the lattice thermal conductivity of semimetallic tantalum nitride in the θ-phase (θ-TaN) can be as high as 1000Wm^-1K^-1, and an experimental study has synthesized the θ-TaN polycrystal samples and observed that the thermal conductivity of the experimental samples is primarily limited by grain boundary scattering. Here, by using density functional theory calculations, we introduce a detailed computational study of the thermal conductivity of θ-TaN series compounds, such as hafnium nitride (HfN) and tantalum carbide (TaC). We discuss possible optimization methods to increase the thermal conductivity which is the sum of lattice thermal conductivity and electronic thermal conductivity in semimetallic system.