Theoretical study of PbZrTiO₃and PbSnZrTiO₃using a total-energy planewave-pseudopotential method

The structural, electronic and optical properties of PbZrTiO3 (PZT) and PbSnZrTiO3 (PSnZT) have been studied by a quantum-mechanical calculation using a total-energy pseudopotential code. This compound has a tetragonal crystal structure with space group P4mm of a ferroelectric phase. Different compositions of titanium (Ti) and zirconium (Zr) in PZT and PSnZT were varied with Ti/Zr composition of 33/66, 50/50, and 66/33. It is found that the different compositions of Ti/Zr have changed the lattices and the band structure of both materials. The cohesive energy was calculated to predict the most suitable composition for modification in PZT and PSnZT. The refractive index under the change of Ti/Zr composition was also investigated. The PZT and PSnZT compounds may be promising materials for future ferroelectric and piezoelectric applications.