Suppressing Thermal Conductivity in SrTiO by Introducing Oxygen Isotope Disorder.

Transition metal oxides are promising candidates in the field of thermoelectricity, which can convert heat and electricity into each other and realize the efficient utilization of waste energy. For the figure of merit = σ/(κ + κ), a lower thermal conductivity is desired for an enhanced , and cation doping is an appropriate way to regulate the thermal transport properties. However, because , σ, and κ are strongly coupled with each other, cation doping for one parameter modification can generate compensation with others, making regulation more difficult. In this work, we demonstrate the effective engineering of the thermal conductivity of SrTiO films by partial oxygen isotope substitution with O using a straightforward aftergrowth thermal annealing process. The results show that the isotope disorder promotes the scattering of phonons and generates a nearly 20% decreased thermal conductivity of SrTiO films. Our work provides a convenient new route for the design of thermoelectric materials with high values.