Magnetism, Electronic Structure, and Dynamics in Atomic Clusters

原子团簇中的磁性、电子结构和动力学

• 批准号: 0098781
• 负责人: Louis Bloomfield
• 金额: $ 20万
• 依托单位: University of Virginia Main Campus
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-06-01 至 2004-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0098781&HistoricalAwards=false
• 关键词: Magnetism; Electronic; Structure; Dynamics; Atomic

This experimental research project uses small clusters of atoms to examine the development of several bulk characteristics and phenomena-magnetism, structural defects, and phase transitions-out of molecular properties. Its main thrusts are in magnetic ordering in ferro- and ferri-magnetic particles and in ultrafast ion and electron dynamics in salt systems. The magnetic component seeks to address numerous theoretical uncertainties in the spin ordering of low-dimensional systems. Predictions of enhanced ferromagnetic ordering and even elevated Curie temperatures have been predicted in one- and two-dimensional systems, and small particles, with their large fraction of surface atoms, are proving to be an excellent laboratory in which to study such effects. Spin-canting and a competition between ferro- and antiferromagnetic orderings have also been examined theoretically and will be studied in this work. The dynamics portion examines the interactions of alkali-halide clusters with light, looking at the roles of various energies-thermal, electronic, vibrational, and rotational-in the finite-system equivalents of heating, cooling, melting, and evaporating. Graduate students participating in this research will receive training that will prepare them for industrial, academic, or government careers in the rapidly developing fields of optical science and engineering and nanotechnology, particularly the emerging fields of magnetic and non-volatile charge-based memory and optical computing.This research uses small collections of atoms to examine connections between the science of individual atoms and molecules and the science of bulk matter. In particular, it studies how bulk magnetic properties emerge from those of the individual atoms that comprise bulk matter and how temperature, melting, and evaporation are related to various dynamic phenomena in small molecules. Both experimental programs involve beams of tiny particles in vacuum, so that those particles are studied in the pristine state of perfect isolation. They are therefore well-suited to address many fundamental questions, including how the magnetic atoms in a material order themselves to retain or cancel their magnetism in larger system, how light energy heats small systems, and how large a particle has to be in order to exhibit such bulk properties and phenomena as temperature, crystal structure, and changes of material phase. This research has close connections with modern magnetic and electronic memory systems and with optical storage and communications. Students in this research program undergo rigorous training in condensed matter, atomic, molecular, and optical physics and are well prepared for careers in industrial or academic science.

该实验研究项目使用小原子团来研究分子特性的几种体特性和现象（磁性、结构缺陷和相变）的发展。其主要研究方向是铁磁性粒子和亚铁磁性粒子的磁有序性以及盐系统中的超快离子和电子动力学。 磁性组件旨在解决低维系统自旋排序中的许多理论不确定性。 人们在一维和二维系统中预测了铁磁有序性增强，甚至居里温度升高，而小颗粒及其大量表面原子被证明是研究此类效应的绝佳实验室。 自旋倾斜以及铁磁和反铁磁有序之间的竞争也已在理论上得到检验，并将在本工作中进行研究。 动力学部分研究碱卤化物簇与光的相互作用，研究各种能量（热能、电子能、振动能和旋转能）在加热、冷却、熔化和蒸发的有限系统等效物中的作用。 参与这项研究的研究生将接受培训，为他们在快速发展的光学科学与工程和纳米技术领域，特别是磁性和非易失性基于电荷的存储器和光学计算领域的工业、学术或政府职业做好准备。这项研究使用小型原子集合来检验单个原子和分子科学与大块物质科学之间的联系。 特别是，它研究了构成大块物质的单个原子的整体磁性如何产生，以及温度、熔化和蒸发如何与小分子中的各种动态现象相关。 这两个实验项目都涉及真空中的微小粒子束，因此这些粒子是在完美隔离的原始状态下进行研究的。 因此，它们非常适合解决许多基本问题，包括材料中的磁性原子如何在较大的系统中自行排列以保留或消除其磁性，光能如何加热小系统，以及粒子必须有多大才能表现出诸如温度、晶体结构和材料相变化等整体特性和现象。 这项研究与现代磁性和电子存储系统以及光学存储和通信有着密切的联系。 该研究项目的学生接受凝聚态、原子、分子和光学物理学方面的严格培训，为工业或学术科学领域的职业生涯做好充分准备。