| Abstract Scope |
We investigate charge and heat transport kinetics of bulk polycrystalline Y- and La-doped CaO(CaMnO<sub>3</sub>)<sub>m</sub> compounds for thermoelectric energy conversion at elevated temperatures. These layered compounds comprise m-perovskite sub-cells separated by CaO-planes, which are tuned by altering their crystal periodicities. Employing high-resolution transmission electron microscopy, we show that both Y and La substitute for Ca sites. We analyze the temperature-dependent electronic transport properties considering the small polaron hopping model in combination with first-principles calculations of elastic properties, indicating tight correlation between charge transport and lattice elasticity. Interestingly, the polaron hopping energies of Y-doped compounds are lower than those of their La-doped counterparts. A fundamental model for elastically isotropic materials indicates that the elastic energy induced by small polarons corresponds with the polaron hopping energies. Our study shows strong coupling between charge carrier dynamics and elastic properties, with implications for charge carrier mobility engineering. |