We investigate the effect of A -site size differences in the double perovskites BiScO3-M NbO3 (M=Na, K, and Rb) using first-principles calculations. We find that the polarization of these materials is 70-90 μC/cm2 along the rhombohedral direction. The main contribution to the high polarization comes from large off-centerings of Bi ions, which are strongly enhanced by the suppression of octahedral tilts as the M -ion size increases. A high Born effective charge of Nb also contributes to the polarization and this contribution is also enhanced by increasing the M -ion size.
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|Publication status||Published - 2010 Oct 11|
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics