Theoretical Study of Lattice Thermal Conduction in SrTiO3/BaTiO3 Superlattice Nanowires

In this paper, environmental friendly materials thermoelectric oxides are chosen as research directions, and the perovskite oxide SrTiO3 based superlattice is selected as a material system for thermoelectric power generation. Combined with diffuse interface boundary conditions Boltzmann transport equation based on diffuse mismatch model is used to calculate thermal conductivities of SrTiO3/BaTiO3 nanowires. The thermal conductivities of SrTiO3/BaTiO3 nanowires with length segments of 5 nm each having diameters of samples 0.44 nm, 0.55nm, 0.75 nm, 1.18 nm and 1.58 nm were measured at room temperature and the thermal conductivities of SrTiO3/BaTiO3 nanowires samples with the diameters of 5 nm each, having equal length segments of 16 nm, 21 nm, 33 nm, 45 nm and 57 nm were measured at room temperature. Reduced effective thermal conductivity of superlattice nanowire was found to be 0.5 W/mK for dw =0.44 nm and L=5 nm. The obtained conclusion suggests the idea that SrTiO3/BaTiO3 superlattice nanowire can be a very good candidate for thermoelectric performance by reducing the periodic length and the wire cross-sectional width. Finally we also concluded that the thermal conductivity of the nanowire reduce more effectively due to reduction in diameter of nanowire in comparison to reduction in its periodic length.