کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1560741 | 1513918 | 2014 | 5 صفحه PDF | دانلود رایگان |
• We propose a global optimization method based on the genetic algorithm (GA).
• We predict the true ground states in 1:1 and 2:2 BaTiO3/CaTiO3 superlattices.
• We reveal a new mechanism for enhancing the electric polarization in 1:1 BaTiO3/CaTiO3 superlattice.
Interface engineering in perovskite oxide superlattices has developed into a flourishing field, enabling not only further tuning of the exceptional properties, but also giving access to emergent physical phenomena. Here, we reveal a new mechanism for enhancing the electric polarization by the interface-induced oxygen octahedral tilts in BaTiO3/CaTiO3 superlattices. By combining a novel genetic algorithm with density functional theory (DFT), we predict that the true ground states in 1:1 and 2:2 BaTiO3/CaTiO3 superlattices grown on SrTiO3 adopt Pc symmetry with a large proper electric polarization (32.8 μC/cm2 for 1:1 and 35.8 μC/cm2 for 2:2 superlattices), which is even larger than that of bulk BaTiO3. The tilt of oxygen octahedron is found to play a key role for the enhancement of out-of-plane polarization in 1:1 superlattices because it reduces greatly the rotation of oxygen octahedron (out-of-phase) which significantly suppresses the out-of-plane polarization.
Figure optionsDownload as PowerPoint slide
Journal: Computational Materials Science - Volume 91, August 2014, Pages 310–314