Parameterization of Dielectric Functions and Phase Transitions of SrTiO3 from 26 to 674 K

Abstract

We present parameters that allow the dielectric function (ε = ε1 + iε2) of perovskite SrTiO3 (STO) to be calculated for spectral range from 0.74 to 6.42 eV and temperatures from 26 to 674 K. The ε data of STO were reproduced from a previous report. We use the Tauc-Lorentz model to express ε of STO analytically for each temperature. The ε spectra are successfully parameterized with six Tauc-Lorentz components and a pole. To obtain ε data for arbitrary energies and temperatures over the range given above, we interpolated the parameterized results using cubic polynomials. It is well known that STO has phase transitions near 40 and 105 K, which are reflected well in our modeling. Our data allow complex refractive indices to be calculated at any temperature for device design.