NSF-Europe: Nanoscale Ferroelectric and Piezoelectric Phenomena in Ultrathin Oxide Heterostructures

这是马里兰大学和德国亚琛莱茵-威斯特法利斯理工大学（RWTH）的研究人员之间的合作项目。该项目旨在创建铁电纳米结构并表征其极化动力学。早期的工作表明，铁电极化在70 nm3的横向尺寸下表现良好。当铁电体积缩小到几纳米时，会产生热激发（kT）和偶极相互作用之间的竞争，导致极性态的存在。研究活动主要集中在两个方面：探索这些薄膜的尺寸缩放效应；并全面了解影响这些材料功能的纳米级动力学现象。一个主要的挑战是在纳米尺度上制造和整合功能氧化物与其他材料，并确定和了解它们的性质。该项目期望通过结合先进的材料加工和制造方法，结合最先进的纳米光刻工具（如聚焦离子束铣削和电子束光刻）来创建纳米结构，以及使用各种纳米级分辨率探针来研究和理解纳米级的动态物理现象，从而取得进展。亚琛的活动将强调先进的设备处理，而扫描探针的特性将在马里兰解决。此外，这两个机构将参与计算和理论建模。该项目涉及与具有技术相关性的电子材料相关的基础研究问题。该项目的一个重要特点是非常重视教育，强调研究和教育的整合，以及提供科学和教育效益的国际合作。这种互动的一个重要组成部分将是长时间的学生交换。在夏季，一个学生交换项目将允许马里兰州的研究生在亚琛进行研究，反之亦然。此外，高级成员将在合作伙伴的所在地进行讲座，以进一步促进互动。本项目由美国国家科学基金会多学科活动办公室、材料研究部（电子材料和陶瓷项目）和国际办公室（西欧）共同资助，作为美国国家科学基金会与欧洲材料研究合作项目（NSF 02-135）。该项目是与德国亚琛莱茵-威斯特法利斯理工大学（RWTH）合作进行的

This is a collaborative project between researchers at the University of Maryland and at Rheinisch-Westfalische Technische Hochschule (RWTH) Aachen, Germany. The project aims to create ferroelectric nanostructures and characterize polarization dynamics in them. Earlier work has shown that ferroelectric polarization is is well-behaved down to lateral sizes of 70 nm3. When the ferroelectric volume shrinks to a few nanometers, there arises a competition between thermal excitation (kT) and dipolar interactions that lead to the existence of a polar state. Re-search activities are focused on two areas: exploration of size scaling effects in these thin films; and comprehensive understanding of nanoscale dynamical phenomena that impact the functional-ity of these materials. A major challenge is to fabricate and integrate functional oxides with other materials at nanometer dimensions, and to determine and understand their properties. This pro-ject expects progress through a combination of advanced materials processing and fabrication approaches, incorporation of state-of-the-art nanolithography tools (such as focused ion beam milling and e- beam lithography) to create nanostructures and the use of a variety of nanoscale resolution probes to study and understand dynamical physical phenomena at the nanoscale. Ac-tivities at Aachen will emphasize advanced device processing, while scanned probe characteriza-tion will be addressed at Maryland. In addition both institutions will participate in computational and theoretical modeling.%%% The project addresses fundamental research issues associated with electronic materials having technological relevance. An important feature of the project is the strong emphasis on education, with emphasis on integration of research and education, and an international collaboration pro-viding both scientific and educational benefits. An important component of this interaction will be exchange of students for extended periods of time. During summers, a student-exchange pro-gram will allow graduate students from Maryland to conduct research in Aachen, and vice versa. Additionally, senior members will present lectures at the partner's location to further foster inter-actions. This NSF project is co-funded by the Office of Multidisciplinary Activities, the Division of Materials Research (Electronic Materials, and Ceramics Programs), and the International Of-fice (Western Europe) as a Cooperative Activity in Materials Research between the NSF and Europe (NSF 02-135). This project is being carried out in collaboration with Rheinisch-Westfalische Technische Hochschule (RWTH) Aachen, Germany.***