Investigation of optical and thermoelectric properties of PbTiO3 under pressure

The electronic, thermoelectric and optical properties of cubic PbTiO3 perovskite's oxides have been investigated under the variation of pressures within the frame work of DFT by using PBEsol-GGA as exchange correlation functional. Band structures show that PbTiO3 is a semiconductor with indirect band gap upto 40 GPa, while the band gap becomes direct at 80 GPa and decreases from 1.99 to 1.5 eV. In order to understand the optical response of PbTiO3, dielectric function (with real and imaginary part) have studied along with the optical conductivity, absorption coefficient, extinction coefficient, reflectivity and refractive index upto 16 eV. It was observed that static dielectric constant decreases with the decrease in energy band gap. Finally, the response of material with respect to temperature at different pressures has been studied by thermal conductivity, electrical conductivity, power factor, Seebeck coefficient and figure of merits by using Boltz-TraP code. Results indicate that PbTiO(3)is a potential candidate for optoelectronic and renewable energy devices.