Thermoelectric Characteristics of Silver-Based Chalcopyrite Semiconductors: An Ab Initio Study Based on the Nonempirical Range-Separated Dielectric-Dependent Hybrid

We explore the intricate domain of thermoelectric phenomena within silver (Ag)-based chalcopyrites, focusing on compositions such as AgXTe2 (where X = Ga, In) and the complex quaternary system Ag2ZnSn/GeY2 (with Y = S, Se). The thermoelectric parameters are estimated from the Boltzmann transport theory in combination with the electronic structures that, in turn, are obtained using the nonempirical screened dielectric-dependent hybrid (DDH) functional approach within the density functional theory (DFT). This approach allows us to analyze critical thermoelectric properties, including electrical conductivity, the Seebeck coefficient, and power factor. We investigate the critical role of phonon scattering by leveraging both the elastic constant tensor and the deformation potential method. This enables a rigorous examination of the electron relaxation time and lattice thermal conductivity, enhancing the robustness of our predictions. We identify materials with a thermoelectric figure of merit (ZT = σS2T/κ) exceeding the critical threshold of unity. Our findings delineate a promising trajectory, laying the groundwork for the emergence of a new class of Ag-based chalcopyrites distinguished by their exceptional thermoelectric characteristics.