Year: 2010
Type: article
Abstract: We present a density-functional theory investigation of strained ${\text{Ca}}_{0.5}{\text{Sr}}_{0.5}{\text{TiO}}_{3}$ (CSTO). We have determined the structure and polarization for a number of arrangements of Ca and Sr in a $2\ifmmode\times\else\texttimes\fi{}2\ifmmode\times\else\texttimes\fi{}2$ supercell. The $a$ and $b$ lattice vectors are strained to match the lattice constants of the rotated Si(001) face. To set the context for the CSTO study, we also include simulations of the Si(001) constrained structures for ${\text{CaTiO}}_{3}$ and ${\text{SrTiO}}_{3}$. Our primary findings are that all ${\text{Ca}}_{0.5}{\text{Sr}}_{0.5}{\text{TiO}}_{3}$ structures examined except one are ferroelectric, exhibiting polarizations ranging from $0.08\text{ }\text{C}/{\text{m}}^{2}$ for the lowest energy configuration to about $0.26\text{ }\text{C}/{\text{m}}^{2}$ for the higher energy configurations. We find that the configurations with larger polarizations have lower $c/a$ ratios. The net polarization of the cell is the result of Ti-O ferroelectric displacements regulated by $A$-site cations.
Source: Physical Review B
Language: Latvian
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W1500538499