Accurate Atomic Structure and Symmetry Determination of New Hybrid Improper Ferroelectric Phases

新型杂化非合适铁电相的准确原子结构和对称性测定

• 批准号: 2313456
• 负责人: Trevor Tyson
• 金额: $ 63.91万
• 依托单位: New Jersey Institute of Technology
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-08-01 至 2026-07-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2313456&HistoricalAwards=false
• 关键词: Accurate; Atomic; Structure; Symmetry; Determination

Non-Technical Abstract. Ferroelectric materials comprise a $7 billion market owing to their unique properties (a spontaneous electric polarization), and find use in many applications such as medical imaging for disease diagnosis, large-scale storage of information such as in data centers, or in high-density energy storage for solar or wind farms for times when these forms of energy are not available. The most common ferroelectric materials utilize elements that are difficult to obtain in nature and/or are toxic. Fortunately, the number of ferroelectric systems has been expanded significantly with the discovery of hybrid improper ferroelectrics, which can be composed of readily available, cheap elements and have low toxicity. The goal of this work is to determine what the atomic structures of these materials are under high pressure, as new unique ones can be created which will have high technological applicability for information storage or energy storage. Graduate and undergraduate students are involved in all levels of this work, including sample preparation, laboratory and synchrotron-based measurements, modeling, and data analysis. Under the direction of the research team and graduate students, Newark-area high school students from under-represented groups are being trained in a seven-week summer research and teaching program on material preparation and advanced materials characterization. It includes a one-week workshop for high school teachers to enable them to implement components of the program into their laboratory experiments. The education and research is a collaboration between the New Jersey Institute of Technology, Rutgers University, the University of Michigan, Brookhaven National Laboratory, Argonne National Laboratory, Lawrence Berkeley National Laboratory, and the SEED program for high school students (American Chemical Society). Technical Abstract. Ferroelectric materials are essential to high-density data storage and are used in solid-state drives, but basic physics requirements for the known materials have limited the chemical and structural space available for the development of new ones. Recently, this space has been significantly expanded with the discovery of hybrid improper ferroelectrics, which have multiple nonpolar distortions that stabilize a polar ferroelectric state. External conditions can stabilize new phases. To fully exploit this new class of ferroelectrics, their full pressure- and temperature-dependent phase diagrams are needed. To develop a detailed understanding of structural changes in the general class of transition metal oxide-based hybrid improper ferroelectrics, single-crystal diffraction measurements as a function of pressure and temperature are being carried out. The derived detail structure is being used to inform density functional theory (DFT) calculations by constraining the crystal structures investigated computationally. Newly discovered phases are being prepared as metastable forms and integrated into ferroelectric-based devices for improved performance. The societal impact of the proposal will come from broadening the range of oxides available for applications in data storage devices and enabling the use of nontoxic earth-abundant materials systems.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.

非技术摘要。 铁电材料由于其独特的特性（自发的电化极化），包括70亿美元的市场，并在许多应用中找到了用于疾病诊断的医学成像，在数据中心中的大规模存储信息，或在这些能源不可用的时间何时用于太阳能或风场的高密度储能中的大规模存储。 最常见的铁电材料利用自然界难以获得的元素和/或有毒。 幸运的是，随着发现混合不当的铁电基质的发现，铁电系统的数量已大大扩大，这些铁电机可以随时可用，便宜的元素且毒性低。 这项工作的目的是确定这些材料在高压下的原子结构，因为可以创建新的独特的结构，该结构可以创建具有高度技术性的信息存储或能源。 研究生和本科生都参与了这项工作的所有级别，包括样本准备，实验室和基于同步加速器的测量，建模和数据分析。 在研究团队和研究生的指导下，来自代表性不足小组的纽瓦克地区高中学生正在接受为期7周的夏季研究和教学计划，培训了材料准备和高级材料表征。 它包括一个为期一周的研讨会，供高中教师使他们能够在实验室实验中实施该计划的组成部分。 教育与研究是新泽西理工学院，罗格斯大学，密歇根大学，布鲁克黑文国家实验室，阿贡国家实验室，劳伦斯·伯克利国家实验室和高中学生种子计划（美国化学学会）之间的合作。 技术摘要。 铁电材料对于高密度数据存储至关重要，可用于固态驱动器，但是对已知材料的基本物理要求限制了可用于开发新的材料的化学和结构空间。 最近，随着混合不当的铁电特性的发现，该空间已经显着扩大，这些铁电静电构成了多种非极性畸变，可稳定极性铁电状态。 外部条件可以稳定新阶段。 为了充分利用这类新的铁电特性，需要它们的全压和温度依赖性相图。 为了详细了解基于过渡金属氧化金属的混合不当的铁电杂种的结构变化，正在执行单晶衍射测量值随压力和温度的函数。 派生的细节结构用于通过约束计算研究的晶体结构来为密度功能理论（DFT）计算提供信息。 新发现的阶段是作为亚稳态形式准备的，并集成到基于铁电的设备中以提高性能。 该提案的社会影响将来自扩大用于数据存储设备中应用的氧化物的范围，并能够使用无毒的地球丰富的材料系统。该奖项反映了NSF的法定任务，并被认为是值得通过基金会的知识分子优点和更广泛影响的审查标准来通过评估来支持的。