Impact of spin-orbit coupling on the thermoelectric properties of h-TaN monolayer

This study investigates the structural, electronic, mechanical and thermoelectric properties of a two-dimensional h-TaN monolayer using first-principles density functional theory and Boltzmann transport theory. The electronic band structure shows a direct band gap of 0.61[Formula: see text]eV without spin-orbit coupling (SOC), which becomes an indirect band gap of 0.39[Formula: see text]eV with SOC. The mechanical analysis confirms that the h-TaN monolayer is elastically stable and isotropic, exhibiting a moderate Young’s modulus of 103.78[Formula: see text]N/m and a Poisson’s ratio of 0.30, indicating a favorable balance between stiffness and flexibility. Thermoelectric performance is evaluated for n- and p-type doping at a fixed carrier concentration of [Formula: see text] cm[Formula: see text] over the temperature range of 250–700[Formula: see text]K with or without SOC. With SOC, the p-type h-TaN monolayer demonstrates superior thermoelectric performance, achieving a maximum conversion efficiency of 8.81% at 700[Formula: see text]K, compared to 5.93% for the n-type. The lattice thermal conductivity decreases significantly from 3.27[Formula: see text]W/m[Formula: see text]K at 300[Formula: see text]K to 1.31[Formula: see text]W/m[Formula: see text]K at 700[Formula: see text]K. These results highlight the dominant role of p-type carriers and establish h-TaN as a mechanically robust and promising candidate for nanoscale thermoelectric devices.