| Abstract Scope |
Metal-insulator transitions (MIT) promise to enhance thermoelectric materials, impacting electrical conductivity in electronic applications. We study complex oxide solid solutions, starting with lead-ruthenate pyrochlore, a strongly electron-correlated conductor. By gradually replacing lead with yttrium, without miscibility gaps, we aim to utilize MIT to enhance thermoelectric within their defect pyrochlore structures. Through quantum physical modeling, we analyze thermoelectric data to unveil underlying scattering mechanisms affecting electrical- and thermal conductivity and carrier concentration. All compounds exhibit p-type- and glass-like thermal conductivities. The metal-like electrical conductivity- and metal-insulator transition series are governed by electron impurity- and Umklapp scattering. On the semiconductor-insulator series, the Mott Variable Range Hopping mechanism was active. Our study reveals a critical MIT at 0.2 moles of yttrium doping independent of temperature, shifting from metal-like to semiconductor-insulator behavior, explained by the Mott-Hubbard mechanism. This research illuminates on fundamental carrier dynamics and phase transitions crucial for understanding thermoelectric and electronic materials. |