铁电双层膜的极化反转特性

The ferroelectric bilayer film is one of the topics at the forefront of international physics in recent years. Recently, theoretical studies have shown that the ferroelectric bilayer films possess some abilities which the ferroelectric thin films have not, such as a remanent polarization increases, large dielectric response, a huge effective pyroelectric response, etc. And by suitably combining of different components of ferroelectric layers, it can be improved the device performance or created new functional properties, which creates new candidate materials and provides new opportunities for the ferroelectric materials device applications. Focusing on the future trends and needs of the ferroelectric bilayer films, and the analysis of contraposesing the applied foreground of ferroelectric bilayer films internationally and the urgent needs to solve the problems, the project proposes the comprehensive conclusions of physical properties for the polarization reversal characteristics of ferroelectric bilayer films. Moreover, the project also carries out the research of discussing how reduce or eliminate the fatigue phenomenon in the process of polarization reversal, and the physical mechanisms of the abnormal phenomena and new functional properties. We expect that the completion of this project, not only have a new understanding of physical properties for ferroelectric bilayer films and a deeper understanding of physical mechanisms for abnormal phenomena in the process of the polarization reversal and new functional properties, but will also provide a certain data background for ferroelectric bilayer films in practice, and theoretical guidance for the development of new high-performance devices.

铁电双层膜是近年来国际物理学的前沿课题之一。近几年来的理论研究表明：铁电双层膜具有铁电薄膜所不及的能力，如剩余极化增大、大的介电响应、巨大的有效热释电响应等。并且通过不同成分的铁电层合适地结合能够改善器件性能，或者创造新的功能性质，为铁电材料在器件上的应用创造了新的候选材料和提供了新的机会。着眼于未来铁电双层膜的发展趋势和需求，本项目针对当前国际上铁电双层膜的应用前景以及亟待解决问题的分析，提出对铁电双层膜极化反转特性进行全面系统的物理性质定论、探讨如何减小或消除极化反转过程中的疲劳现象、产生奇异现象及新的功能性质的物理机制等方面开展研究。我们预计本项目的完成不但能够对铁电双层膜物理性质有新的认识，对极化反转过程中出现的奇异现象及新的功能性质的物理机制有更深刻的理解，也将为铁电双层膜在实际中的应用提供一定的数据背景以及为新的高性能器件的研制提供了理论方向的指导。

铁电双层膜能够改善器件性能和创造新的功能性质，具有铁电块材与铁电薄膜所不及的能力。对铁电双层膜物理机制的深刻认识，将极大地促进铁电材料在各领域的发展。近年来对铁电双层膜物理机制的研究，在理论、实验和应用方面都取得了显著成果。本项目按照原预定计划进行，在一年的研究期间内共发表与本项目相关的学术论文4篇，全部为SCI收录。（1）通过考虑表面过渡层，建立了较实际的铁电双层膜理论模型，并修正了前人所推导的铁电双层膜理论公式，完善了处理铁电双层膜物理性质的理论方法。（2）得到并分析了铁电双层膜极化反转过程中极化、反转电流、反转时间、矫顽场及剩余极化等性质的物理图像，指出界面耦合与表面过渡层对铁电双层膜物理性质的影响。（3）基于分析所得到的铁电双层膜的电滞回线，提出减小或消除极化反转过程中疲劳现象的方法。（4）预言了在铁电双层膜极化反转过程中，剩余极化、矫顽场及反转时间分别存在一个临界点，当超过这个临界点就会产生奇异现象，并发现了产生这种奇异现象的物理机制。