First Principles Calculation of Tetragonal (P4 mm) Pb-free Ferroelectric Oxide of SnTiO3

• Published in: Ferroelectrics Vol. 459; no. 1; pp. 134 - 142
• Main Authors: Taib, M. F. M., Yaakob, M. K., Badrudin, F. W., Kudin, T. I. T., Hassan, O. H., Yahya, M. Z. A.
• Format: Journal Article
• Language: English
• Published: Taylor & Francis Group 03-01-2014
• Subjects: Density functional theory (DFT); elastic constant; electronic properties; optical properties
• ISSN: 0015-0193; 1563-5112
• DOI: 10.1080/00150193.2013.849178

The properties of tetragonal (P4 mm, 99 space group) SnTiO
3
were investigated via first-principles implemented in CASTEP computer code. The calculation of formation energy shows that the tetragonal P4 mm with the lowest energy optimization is at the ground state equilibrium structure compared to the ilmenite structure. The result also shows that SnTiO
3
has a higher tetragonality (c/a = 1.18). Moreover, the elastic constant of SnTiO
3
also confirmed that this compound has the tetragonal phase with a good mechanical stability. The electronic properties also indicated that the hybridizations occur among anion O 2p, cation Sn 5s and the Ti 3d states with an indirect band gap at the X-G point. The optical properties of SnTiO
3
were determined by the complex dielectric constant and refractive index and they were compared to PbTiO
3
.