Phase transition enhanced thermoelectric performance for perovskites: The case of AgTaO3

In general, perovskite materials, such as AgTaO3, can exhibit complex structural phase transitions when the temperature changes. Different phase structures may show distinct thermoelectric properties. However, the ef-fects of phase transition on the thermoelectric performance of AgTaO3 have yet to be systematically investigated. Thus, in this work, the electronic structures and thermoelectric properties of the p-type AgTaO3 in various phase structures are investigated by utilizing first-principles calculations and semi-classical Boltzmann transport the-ory. The results show that the p-type AgTaO3 in the cubic phase shows a superior power factor because the cubic phase possesses a large Seebeck coefficient and intermediate electrical conductivity. The calculated thermo-electric performance is consistent with the predictions and explanations from the analyses of the electronic structures. When the p-type AgTaO3 is transformed from the tetragonal phase to the cubic phase, its power factor is tripled, suggesting that a suitable phase transition can improve the thermoelectric properties of perovskites.