NIRT: Strain-Enhanced Nanoscale Ferroelectrics

NIRT：应变增强纳米级铁电体

• 批准号: 0507146
• 负责人: Long-Qing Chen
• 金额: --
• 依托单位: Pennsylvania State Univ University Park
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-07-01 至 2011-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0507146&HistoricalAwards=false
• 关键词: NIRT; Strain; Enhanced; Nanoscale; Ferroelectrics

NON-TECHNICAL DESCRIPTION: For many years molecular beam epitaxy (MBE) has been used to build layered semiconductor nanostructures atom-by-atom to investigate and improve our understanding of semiconductor physics and create new devices. These devices (which include laser diodes, high-performance transistors, and magnetic field sensors) have advanced healthcare, national security, communications, entertainment, and transportation-resulting in significant improvements in the quality of life for all Americans. Recent progress in research has demonstrated that this same atom-by-atom synthesis technique can be used to build nanostructures of oxides, including ferroelectrics, with comparable nanometer-scale layering control. Since ferroelectric materials exhibit a wide variety of electrical, optical, and electromechanical properties, they are extensively used in healthcare (e.g., medical ultrasound), national defense (e.g., night vision and sonar systems), and communications (e.g., miniature capacitors for cell phones and computers). The ability to customize the layering of ferroelectric materials at the atomic-layer level and strain them opens exciting possibilities to dramatically enhance their properties. The improved understanding gained via this research will be applied to the development of improved optical and acoustic devices. Future scientists in a highly interdisciplinary research environment in a technologically significant area of national importance will be trained and educated within this program. Professors from Pennsylvania State University, University of Wisconsin, University of Michigan and Rutgers University will run hands-on workshops during the summers at each of the campuses involved in this research team to expose K-12 students to the thrill of science.TECHNICAL DETAILS: The technical objective is to understand the fundamental science underlying the electric, magnetic, and optical responses of strained nanoscale ferroelectrics and multiferroics. An integrated theoretical and experimental effort will be taken. Specifically, "first-principles effective Hamiltonian" approaches based on lattice Wannier functions and Landau-Ginzburg type phenomenological methods will be used to identify ferroelectric and multiferroic materials and heterostructures in which large enhancements in properties are expected with strain. Films will be grown by MBE and laser-MBE, patterned by focused ion beams, and characterized using a combination of x ray diffraction, analytical and transmission electron microscopy, Raman spectroscopy, second harmonic generation, and ferroelectric measurements, all as a function of temperature. Strain is utilized in many semiconductor device structures to improve the transport properties of thin semiconductor layers. Within this project, it will be used to enhance the properties of ferroelectrics. Ferroelectrics are very sensitive to strain and a distinct advantage of thin ferroelectric materials over their bulk counterparts is that they may be strained well beyond where their bulk counterparts would crack. For nanoscale ferroelectrics, huge strains become accessible. This feature combined with the ability to precisely integrate and engineer oxides at the atomic level provides a means to investigate, develop, and exploit the properties of oxides for optical modulators, two-dimensional photonic bandgap structures, and phonon-confining piezoelectric structures relevant to the long-term realization of a phonon laser.

非技术描述：多年来，分子束外延（MBE）一直用于构建分层的半导体纳米结构原子原子，以研究和提高我们对半导体物理学的理解并创建新设备。 这些设备（包括激光二极管，高性能晶体管和磁场传感器）具有先进的医疗保健，国家安全，通信，娱乐和运输剂，以显着改善所有美国人的生活质量。 研究的最新进展表明，这种相同的逐种原子合成技术可用于构建具有可比的纳米尺度分层控制的氧化物，包括铁电的纳米结构。 由于铁电材料具有多种电气，光学和机电特性，因此它们在医疗保健（例如医疗超声），国防（例如夜视和声纳系统）以及通信（例如，用于手机和计算机）的医疗保健中广泛使用。 自定义在原子层水平上定制铁电材料并劳累的能力为显着增强其性质的激动人心的可能性。 通过这项研究获得的改善理解将应用于改进的光学和声学设备的开发。 在该计划中，将在高度跨学科的研究环境中进行高度跨学科的研究环境中的未来科学家进行培训和教育。 Professors from Pennsylvania State University, University of Wisconsin, University of Michigan and Rutgers University will run hands-on workshops during the summers at each of the campuses involved in this research team to expose K-12 students to the thrill of science.TECHNICAL DETAILS: The technical objective is to understand the fundamental science underlying the electric, magnetic, and optical responses of strained nanoscale ferroelectrics and multiferroics.将采取综合的理论和实验努力。 具体而言，将使用基于晶格的Wannier功能和Landau-Ginzburg现象学方法的“第一原理有效的哈密顿式”方法来识别铁电和多表面材料和异质结构，其中预期具有应变的物业中大大增强。 膜将由MBE和Laser-MBE生长，由聚焦离子束模式，并使用X射线衍射，分析和透射电子显微镜，拉曼光谱，第二谐波产生和铁电测量的组合来表征，所有这些都作为温度的功能。 应变用于许多半导体装置结构，以改善薄半导体层的传输特性。 在该项目中，它将用于增强铁电的性质。 铁电基因对菌株非常敏感，而薄铁电材料比其大容量的优势具有明显的优势，因为它们可能会远远超出其大体对应物会破裂的位置。 对于纳米级铁电特性，巨大的菌株变得可及。 该特征结合了在原子水平上精确整合和工程氧化物的能力，提供了一种用于调查，开发和利用氧化物的特性，用于光学调节剂，二维光子波段隙结构以及与声子激光器的长期实现相关的指控Piezoelectric结构。