First-Principles Study on Crystal Structure and Piezoelectricity of Perovskite-Type Silicon Oxides

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Biocompatible piezoelectric materials are becoming increasingly important for actuators and sensors in medical devices. In this study, we examined the possibility of five perovskite-type silicon oxides MgSiO3, MnSiO3, FeSiO3, ZnSiO3 and CaSiO3, which have been found from the stable combinations of biocompatible elements in our previous studies, by employing first-principles DFT. At first, the stable cubic structure and the phonon properties were analyzed for the paraelectric non-polar phase. After the promising silicon oxides were distinguished with the phonon eigenfrequency and eigenvector in consideration of the structural phase transition, their characteristics of stable tetragonal structure were then analyzed for the ferroelectric phase. Computations indicated that MgSiO3 has superiority on the phase transition from cubic structure to tetragonal one. Additionally, tetragonal MgSiO3 has a large spontaneous polarization and it can exhibit a good piezoelectric response.