We have investigated the thermoelectric (TE) properties for single crystals of the perovskites Sr1-xCaxTi1-yNbyO3 for 0 ≤ x ≤ 0.4 and 0 ≤ y ≤ 0.03 at temperatures below room temperature (RT). We found that SrTi0.99Nb0.01O3 showed a large power factor at low temperatures (PF = 50 μW/K2cm at 100 K ∼ 90 μW/K2cm at 50 K) and the largest dimensionless TE figure-ofmerit at temperatures below 40 K (ZT ∼ 0.07) among the reported materials. Such a large low-temperature TE response around a carrier concentration of 1020 cm-3 is due to a distinct phonon drag effect. We also found that the Ca2+ substitution for Sr2+ increased the ZT at 300 K for Sr1-xCaxTi0.97Nb0.03O3 from 0.08 to 0.105. The enhancement of the ZT around RT originates both from a large reduction of a thermal conductivity due to a randomness introduced into the crystal structure and from an unexpected enhancement of a Seebeck coefficient.
|Number of pages||5|
|Journal||Journal of the Korean Physical Society|
|Publication status||Published - 2013 Aug|
- Phonon drag
- Thermoelectric material
ASJC Scopus subject areas
- Physics and Astronomy(all)