Thermal Stability of Giant Thermoelectric Seebeck Coefficient for SrTiO₃/SrTi_0.8Nb_0.2O₃Superlattices at 900 K

Abstract

Herein we report the carrier transport properties of [(SrTiO3)x/(SrTi0.8Nb0.2O3)1]20 (x=0–50) superlattices at high temperatures (T=300–900 K). Significant structural changes were not observed in the superlattices after annealing at 900 K in a vacuum. The Seebeck coefficient of the [(SrTiO3)20/(SrTi0.8Nb0.2O3)1]20 superlattice, which was 300 µV·K-1 at room temperature, gradually increased with temperature and reached 450 µV·K-1 at 900 K, which is ∼3 times larger than that of bulk SrTi0.8Nb0.2O3. These observations provide clear evidence that the superlattice is stable and exhibits a giant Seebeck coefficient even at high temperature.