Insights into structural, Electronic and Thermoelectric properties of ZnTMN2 (TM= Zr and Hf): A First-Principles study

We employ first-principles calculations combined with semi classical Boltzmann transport theory to investigate the structural, electronic, and thermoelectric properties of ZnTMN2 (TM= Zr and Hf). The negative value of formation energy confirms the stability of these compounds. We used Tran Blaha modified Becke Johnson approximation to calculate electronic properties. ZnZrN2 and ZnHfN2 are having indirect bands of magnitude 2.77 eV and 3.31 eV, respectively. The positive value of the Seebeck Coefficient at all studied temperatures confirms its p-type nature. The thermal conductivity slightly decreases with a rise in temperature in ZnHfN2 as compared to ZnZrN2. The observed value of the figure of merit is 0.80 and 0.81 at 500 K and 600 K for ZnZrN2 and ZnHfN2, respectively. The high figure of merit of Hf and Zr-based nitrides make them a potential material for thermoelectric energy harvesting applications.