Thermoelectric optimization using first principles calculation and single parabolic band model: a case of the heavily doped oxide semiconductor

Conducting optimization calculations for thermoelectric performance can be beneficial in guiding the direction of further experimental work. In our study, we utilize a combination of the first principle and restructured single parabolic band model to investigate heavily doped semiconductors based on manganite. Ca0.5L0.5MnO3 (CLMO) and Ca0.5L0.25Bi0.25MnO3 (CLBMO) as samples shows optimization of 30% and 69% respectively at a temperature of 800 K from their respective optimal values. In addition, both samples show two to three orders of magnitude smaller lattice thermal conductivity than their electronic thermal conductivity. This excludes complex phononic transport mechanisms from the calculation of the figure of merit (ZT). The ZT calculations of CLMO and CLBMO are corrected by the ratio of the transport relaxation time of electrical conductivity to the transport relaxation time of electronic thermal conductivity, resulting in ZT values of 0.063 and 0.327 at a temperature of 800 K, respectively.