Abstract
Short-period ferroelectric/ferroelectric (PTO)/ (BTO) superlattices are studied using density functional theory. Contrary to the trends in paraelectric/ferroelectric superlattices the polarization remains nearly constant for PTO concentrations below 50%. In addition, a significant decrease in the ratio below the PTO values was observed. Using a first-principles superlattice model we predict an enhancement in the piezoelectric coefficient peaking at PTO concentration due to the different polarization-strain coupling in PTO and BTO layers. Further analysis reveals that these trends are bulk properties which are a consequence of the reduced brought about by the polarization saturation in the BTO layers.
- Received 16 March 2009
DOI:https://doi.org/10.1103/PhysRevB.79.180101
©2009 American Physical Society