Mechanically controllable nonlinear dielectrics.

Ko, D L; Tsai, M F; Chen, J W; Shao, P W; Tan, Y Z; Wang, J J; Ho, S Z; Lai, Y H et al. · Sci Adv · 2020

basic_science · Level V

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Abstract

Strain-sensitive Ba <i><sub>x</sub></i> Sr<sub>1-<i>x</i></sub> TiO<sub>3</sub> perovskite systems are widely used because of their superior nonlinear dielectric behaviors. In this research, new heterostructures including paraelectric Ba<sub>0.5</sub>Sr<sub>0.5</sub>TiO<sub>3</sub> (BSTO) and ferroelectric BaTiO<sub>3</sub> (BTO) materials were epitaxially fabricated on flexible muscovite substrate. Through simple bending, the application of mechanical force can regulate the dielectric constant of BSTO from -77 to 36% and the channel current of BTO-based ferroelectric field effect transistor by two orders. The detailed mechanism was studied through the exploration of phase transition and determination of band structure. In addition, the phase-field simulations were implemented to provide theoretical support. This research opens a new avenue for mechanically controllable components based on high-quality oxide heteroepitaxy.