The electronic, structural, ferroelectric and optical properties of strontium and zirconium co-doped BaTiO[formula omitted]: First-principles calculations

Abstract

Based on the first-principles calculations, we investigated the electronic, structural, ferroelectric and optical properties of (Ba0.875Sr0.125)(Zr0.125Ti0.875)O3(BSZT). The optimized structure and electron charge density analysis show that the tetragonal structure of BaTiO3 is distorted after doping with Sr and Zr, and the displacement of Zr atoms in the same layer is observed to be smaller than that of Ti atoms. The double potential well curves of pure BaTiO3 and BSZT fit well with the Landau–Ginzburg model. Meanwhile, the spontaneous polarization of BSZT is smaller than that of pure BaTiO3. Furthermore, the analysis of the density of states demonstrates that the ferroelectric properties of the BSZT material are derived from the strong hybridization between Ti 3d, Zr 4d and O 2p orbitals. Finally, we calculated the optical properties such as the real ϵ1(ω) and imaginary ϵ2(ω) part of the complex dielectric function, absorption coefficient α(ω), energy loss function L(ω), reflectivity R(ω) and refractive index n(ω) of BSZT and pure BaTiO3. The results show that the optical properties of BSZT are blue-shifted and exhibit good optical response in the UV region with the appearance of new peaks. The increase of band gap and the change of optical properties suggest that BSZT can be effectively used in ceramic capacitors, resistors with high dielectric insulation and optoelectronic devices.