Self-Assembled Polvdomain Ferroelectric Heterostructures

这是一个合作的理论和实验项目，旨在研究铁电多畴异质结构，目的是实现对材料物理的更好理解，并能够通过控制自组装氧化铁电薄膜的多畴结构来建模和设计异质结构，以增强电学和机械性能。具有多孪晶（90度域）的异质结构将首先考虑。石墨外延方法将用于设计具有可控域分数和周期的多域架构。表征将包括内应力和位错的信息。重点将是了解结构特征如何影响极化的演变。铁电异相多畴异质结构的研究是一种自然的延伸。弛豫型单晶薄膜中的菱形-四方相变为实现这一目标提供了极好的机会。这种转变伴随着显著的应变。因此，弹性相互作用将决定两相多畴态的结构。计划创建这些结构并研究它们的机电性能。该项目涉及具有高潜在技术相关性的材料科学主题领域的基础研究问题。这个合作的跨学科项目的一个重要特点是理论和实验相结合的方法，通过对学生在一个基础和技术重要领域的培训，将研究和教育结合起来。＊＊＊

This is a collaborative theoretical and experimental project to study ferroelectric polydomain heterostructures with the objective of achieving greater materials physics understanding and the ability to model and engineer heterostructures with controlled self-assembled polydomain architecture of oxide ferroelectric films for enhanced electrical and mechanical properties. Heterostructures with polytwins (90 deg.-domains) will be considered first. Graphoepitaxial methods will be used to engineer polydomain architectures with controlled domain fractions and periods. Characterization will include information on internal stresses and dislocations. The focus will be to understand how structural characteristics affect the evolution of polarization. A natural extension is the study of ferroelectric heterophase polydomain heterostructures. The rhombohedral-tetragonal phase transformation in relaxor type single crystalline films offers an excellent opportunity to do so. This transformation is accompanied by a significant strain. Therefore, elastic interactions will determine the architecture of the two-phase polydomain state. It is planned to create these architectures and study their electro-mechanical properties as well.%%%The project addresses basic research issues in a topical area of materials science having high potential technological relevance. An important feature of this collaborative, interdisciplinary program is the combined theoretical and experimental approach, and the integration of research and education through the training of students in a fundamentally and technologically significant area. ***