Using density-functional calculations we study the structure and polarization response of tetragonal PbTiO3, BaTiO3 and SrTiO3 in a strain regime that is previously overlooked. Different from common expectations, we find that the polarizations in all three substances saturate at large strains, demonstrating a universal phenomenon. The saturation is shown to originate from an unusual and strong electron-ion correlation that leads to cancellation between electronic and ionic polarizations. Our results shed new insight on the polarization properties, and reveal the existence of a fundamental limit to the strain-induced polarization enhancement.
@article{arxiv.0804.0630,
title = {Polarization Saturation in Strained Ferroelectrics},
author = {Yanpeng Yao and Huaxiang Fu},
journal= {arXiv preprint arXiv:0804.0630},
year = {2008}
}