Exploring the Interplay between Charge, Strain and Polarization in Ferroelectric Nanostructures

探索铁电纳米结构中电荷、应变和极化之间的相互作用

• 批准号: 2034738
• 负责人: Xiaoqing Pan
• 金额: $ 64万
• 依托单位: University of California-Irvine
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-03-01 至 2025-02-28
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2034738&HistoricalAwards=false
• 关键词: Exploring; Interplay; between; Charge; Strain

NON-TECHNICAL DESCRIPTION: Ferroelectric materials are characterized by a spontaneous electric polarization, which can be reoriented with an applied electric field. The ability to form and manipulate nanoscale regions of uniform polarization (domains) makes ferroelectrics a promising candidate for future low-power electronic devices, particularly computer memories. When ferroelectrics is integrated with other materials, new and unique properties can emerge from interfaces where the two materials join. To understand these emergent properties, it is critical to characterize the atomic structure, chemical bonding, electric field, charge distribution at interfaces. Modern electron microscopy is capable of directly imaging the atomic structure, but the other properties must generally be inferred from these images. This project aims to develop new imaging methods that enable to determine all of these properties simultaneously. This will give a full picture of how and why unique properties can emerge at the interface and will inform the design and fabrication of future electronic devices. Although the research focuses on ferroelectrics, the microscopy techniques developed during and scientific knowledge gained from this project are broadly applicable to many different types of materials. The research is integrated with education and outreach activities to attract diverse junior scientists, including women and underrepresented minority groups, and will help train future leaders to address critical societal challenges.TECHNICAL DETAILS: This project leverages unique electron microscopy facilities at the Irvine Materials Research Institute where the PI serves as the director. This project aims to develop a novel four-dimensional scanning transmission electron microscopy (4D STEM) method that enables the measurement of atomic scale structure, local electric field, charge density, valence states, and polarization configuration in nanostructures and interfaces under different boundary conditions with atomic resolution. 4D STEM will also be combined with electron energy-loss spectroscopy and scanning probe microscopy in a unique multimodal approach to probe the atomic scale structure and properties of interfaces and to gain a fundamental understanding of the interaction between ferroelectric polarization, bound charge, epitaxial strain, charge screening, and structure reconstruction in ferroelectric interfaces under different conditions or surrounding topological defects in doped ferroelectric thin films. The detailed characterization of ferroelectric interfaces is required to gain deep insights into the atomic mechanisms of emergent phenomena at interfaces and provide guidance for engineering ferroelectric nanostructures with novel functionalities. The integration of this research with the education and training of students allows the results from this project to be disseminated to the diverse student populations on campus through coursework and independent studies for undergraduate students, as well as to high school students from diverse backgrounds through summer school programs, which promotes their interest in scientific research and education.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

非技术描述：铁电材料的特点是自发电极化，它可以在外加电场的作用下重新定向。形成和操纵均匀极化（畴）的纳米级区域的能力使铁电体成为未来低功耗电子器件，特别是计算机存储器的有希望的候选者。当铁电体与其他材料结合在一起时，两种材料结合的界面会产生新的独特的性能。为了理解这些涌现特性，表征原子结构、化学键、电场、界面电荷分布是至关重要的。现代电子显微镜能够直接成像原子结构，但其他性质一般必须从这些图像推断出来。该项目旨在开发能够同时确定所有这些属性的新成像方法。这将给出一个完整的画面，如何以及为什么独特的属性可以在界面上出现，并将为未来电子设备的设计和制造提供信息。虽然研究的重点是铁电体，但该项目期间开发的显微镜技术和从中获得的科学知识广泛适用于许多不同类型的材料。这项研究与教育和推广活动相结合，以吸引不同的青年科学家，包括妇女和代表性不足的少数群体，并将帮助培训未来的领导人来应对关键的社会挑战。技术细节：该项目利用了欧文材料研究所独特的电子显微镜设备，PI担任主任。本项目旨在开发一种新的四维扫描透射电子显微镜（4D STEM）方法，以原子分辨率测量不同边界条件下纳米结构和界面中的原子尺度结构、局部电场、电荷密度、价态和极化配置。4D STEM还将以独特的多模态方法与电子能量损失光谱和扫描探针显微镜相结合，探测界面的原子尺度结构和性质，并对掺杂铁电薄膜中不同条件或周围拓扑缺陷下铁电界面中的铁电极化、束缚电荷、外延应变、电荷筛选和结构重建之间的相互作用有一个基本的了解。铁电界面的详细表征需要深入了解界面出现现象的原子机制，并为具有新功能的铁电纳米结构的工程提供指导。这项研究与学生的教育和培训相结合，使该项目的成果可以通过课程和本科生的独立学习传播给校园内的不同学生群体，也可以通过暑期学校项目传播给不同背景的高中生，从而提高他们对科学研究和教育的兴趣。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

项目成果

Probing charge density in materials with atomic resolution in real space

• DOI: 10.1038/s42254-022-00541-4
• 发表时间: 2022-12
• 期刊: Nature Reviews Physics
• 影响因子: 38.5
• 作者: Christopher Addiego;Wenpei Gao;H. Huyan;Xiaoqing Pan

Direct observation of polarization-induced two-dimensional electron/hole gases at ferroelectric-insulator interface

• DOI: 10.1038/s41535-021-00389-4
• 发表时间: 2021-10-20
• 期刊: NPJ QUANTUM MATERIALS
• 影响因子: 5.7
• 作者: Huyan, Huaixun;Addiego, Christopher;Pan, Xiaoqing
• 通讯作者: Pan, Xiaoqing

Stability-limiting heterointerfaces of perovskite photovoltaics

• DOI: 10.1038/s41586-022-04604-5
• 发表时间: 2022-03-15
• 期刊: NATURE
• 影响因子: 64.8
• 作者: Tan, Shaun;Huang, Tianyi;Yang, Yang
• 通讯作者: Yang, Yang

Emergent properties at oxide interfaces controlled by ferroelectric polarization

• DOI: 10.1038/s41524-021-00601-w
• 发表时间: 2021-08
• 期刊: npj Computational Materials
• 影响因子: 9.7
• 作者: Fan Ye;Yi Zhang;Christopher Addiego;Mingjie Xu;H. Huyan;X. Ren;Xiaoqing Pan