The Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37831, United States of America.
Rep Prog Phys. 2018 Mar;81(3):036502. doi: 10.1088/1361-6633/aa915a.
For over 70 years, ferroelectric materials have been one of the central research topics for condensed matter physics and material science, an interest driven both by fundamental science and applications. However, ferroelectric surfaces, the key component of ferroelectric films and nanostructures, still present a significant theoretical and even conceptual challenge. Indeed, stability of ferroelectric phase per se necessitates screening of polarization charge. At surfaces, this can lead to coupling between ferroelectric and semiconducting properties of material, or with surface (electro) chemistry, going well beyond classical models applicable for ferroelectric interfaces. In this review, we summarize recent studies of surface-screening phenomena in ferroelectrics. We provide a brief overview of the historical understanding of the physics of ferroelectric surfaces, and existing theoretical models that both introduce screening mechanisms and explore the relationship between screening and relevant aspects of ferroelectric functionalities starting from phase stability itself. Given that the majority of ferroelectrics exist in multiple-domain states, we focus on local studies of screening phenomena using scanning probe microscopy techniques. We discuss recent studies of static and dynamic phenomena on ferroelectric surfaces, as well as phenomena observed under lateral transport, light, chemical, and pressure stimuli. We also note that the need for ionic screening renders polarization switching a coupled physical-electrochemical process and discuss the non-trivial phenomena such as chaotic behavior during domain switching that stem from this.
七十多年来，铁电材料一直是凝聚态物理和材料科学的核心研究课题之一，这一研究兴趣既源于基础科学，也源于应用。然而，铁电体表面作为铁电薄膜和纳米结构的关键组成部分，仍然存在着重大的理论甚至概念性挑战。实际上，铁电相的稳定性本身就需要屏蔽极化电荷。在表面，这可能导致铁电和材料的半导体性质之间的耦合，或者与表面（电）化学相互作用，远远超出适用于铁电界面的经典模型。在这篇综述中，我们总结了铁电体表面屏蔽现象的最新研究进展。我们简要回顾了铁电体表面物理学的历史认识，以及现有的理论模型，这些模型既引入了屏蔽机制，又从相稳定性本身出发，探讨了屏蔽与铁电功能相关方面之间的关系。鉴于大多数铁电体存在于多畴状态，我们专注于使用扫描探针显微镜技术对屏蔽现象的局部研究。我们讨论了铁电体表面的静态和动态现象，以及在横向传输、光、化学和压力刺激下观察到的现象。我们还注意到，离子屏蔽的需要使得极化反转成为一个耦合的物理电化学过程，并讨论了由此产生的混沌行为等复杂现象。
