Thermal conductivity reduction in oxygen-deficient strontium titanates

We report significant thermal conductivity reduction in oxygen-deficient lanthanum-doped strontium titanate ( Sr 1 − x La x Ti O 3 − δ ) films as compared to unreduced strontium titanates. Our experimental results suggest that the oxygen vacancies could have played an important role in the reduction. This could be due to the nature of randomly distributed and clustered vacancies, which would be very effective to scatter phonons. Our results could provide a pathway for tailoring the thermal conductivity of complex oxides, which is very beneficial to various applications including thermoelectrics.