Engineering Polarization Rotation in Ferroelectric Bismuth Titanate

TL;DR

This study combines experimental and theoretical methods to explore how doping and strain influence polarization in ferroelectric bismuth titanate, aiming to enable the design of oriented films with enhanced polarization.

Contribution

It demonstrates that simultaneous Bi and Ti site doping can induce moderate polarization along the c-axis, providing a new strategy for designing ferroelectric materials with tailored polarization properties.

Findings

Doping and strain do not significantly increase c-axis polarization as previously reported.

First principles calculations suggest Bi and Ti site doping can induce moderate polarization.

The approach can be applied to other ferroic oxides for tailored polarization in epitaxial films.

Abstract

Here, we report a combined experimental-theoretical study showing that collective application of rare earth doping on A-site and epitaxial strain to ferroelectric bismuth titanate does not lead to a very large c-axis polarization as reported previously. Further first principles calculations based on the examination of polarization tensor suggest that simultaneous Bi and Ti site doping could result in moderate polarization along c-axis of bismuth titanate which is typically a preferential axis of film growth and thus enabling c axis oriented films to have appreciable polarization. This approach could also be applicable to other ferroic oxides where one can correlate the doping, epitaxial strain, and polarization to design materials compositions resulting in epitaxial films grown along desired directions yielding substantial polarization.