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。 铁电材料因其独特的特性（自发电极化）而构成了价值 70 亿美元的市场，并可用于许多应用，例如用于疾病诊断的医学成像、数据中心等大规模信息存储，或者在这些形式的能源不可用时用于太阳能或风电场的高密度能量存储。 最常见的铁电材料使用自然界中难以获得和/或有毒的元素。 幸运的是，随着混合不当铁电体的发现，铁电系统的数量已显着增加，这种铁电体可以由容易获得的廉价元素组成，并且毒性较低。 这项工作的目标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材料，这将对信息存储或能量存储具有较高的技术适用性。 研究生和本科生参与了这项工作的各个层面，包括样品制备、实验室和同步加速器测量、建模和数据分析。 在研究团队和研究生的指导下，纽瓦克地区来自弱势群体的高中生正在接受为期七周的夏季研究和教学计划，内容涉及材料制备和高级材料表征。 它包括为高中教师举办为期一周的研讨会，使他们能够将该计划的组成部分应用到实验室实验中。 该教育和研究是新泽西理工学院、罗格斯大学、密歇根大学、布鲁克海文国家实验室、阿贡国家实验室、劳伦斯伯克利国家实验室和面向高中生的 SEED 计划（美国化学会）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，并用于固态驱动器，但已知材料的基本物理要求限制了可用于开发新材料的化学和结构空间。 最近，随着混合不合适铁电体的发现，这一领域得到了显着扩展，这种铁电体具有多种非极性畸变，可以稳定极性铁电态。 外部条件可以稳定新的阶段。 为了充分利用这种新型铁电体，需要完整的压力和温度相关相图。 为了详细了解一般类型的基于过渡金属氧化物的混合不合适铁电体的结构变化，正在进行单晶衍射测量作为压力和温度的函数。 导出的详细结构通过约束计算研究的晶体结构来为密度泛函理论（DFT）计算提供信息。 新发现的相正在被制备为亚稳态形式，并集成到基于铁电的器件中以提高性能。 该提案的社会影响将来自于扩大可用于数据存储设备的氧化物范围，并支持使用地球上丰富的无毒材料系统。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。