Electronic Properties of Reduced-Dimensional, Supported Metals

降维负载金属的电子特性

• 批准号: 0504654
• 负责人: Phillip Sprunger
• 金额: --
• 依托单位: Louisiana State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-07-01 至 2009-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0504654&HistoricalAwards=false
• 关键词: Electronic; Properties; Reduced; Dimensional; Supported

**** NON-TECHNICAL ABSTRACT ****Electronic properties in nanoscale materials are quite different from those in macroscopic materials. The properties of electrons, which dictate nearly all physical, electronic, magnetic, and chemical properties, become more and more "exotic" as the size of the material decreases. This study will use both experiment and theory to reveal the quantum physics underlying the behavior of metals as their dimensions decrease from 3-D macroscopic materials to 2-D surfaces and thin-films that have nanometer thicknesses, to 1-D nanowires that can be quite long but have cross-sections of only nanometers. These nanoscale metal structures will be fabricated using approaches that allow one to "turn-the-knob" of atomic dimensionality. By adjusting the "surface-to-volume ratio" atom-by-atom this project will tune the underlying electronic structure and physical properties. Utilizing state-of-the-art experimental techniques, such as scanning probe microscopy and synchrotron-based photoelectron spectroscopy, the properties of supported nanoscale metals will be characterized. A key ingredient of this study will be to correlate experimentally observed atomic and electronic properties of supported nanoscale metals with theoretical calculations. This research is expected to enhance our basic understanding of materials with dimensions on the nanoscale, where "exotic" electron interactions allow the development of a new generation of novel electronic, magnetic, photonic, and catalytic devices. Both graduate and undergraduate students will be involved in this project. They will gain knowledge and learn skills that will enable them to become productive researchers in a field of academic and technological interest. In addition the researchers will endeavor to bring the excitement of science to both K-12 children and the general population in a region of the U.S. known for its diversity and its significant educational and economic challenges, the deep South.**** TECHNICAL ABSTRACT ****This award supports both experimental and theoretical investigations of electronic properties of reduced-dimensional, supported metals. The underlying theme is to understand the roles that spatial size, arrangement, and dimension play in establishing the ensuing electronic properties of nanophase metallic materials. This study will probe the underlying physics (e.g. quantum size effects, many body effects, hybridization) of metals as the dimensionality decreases from bulk to 2-D (surface/ultra thin-film) to 1-D (nanowire) to quantum well/nano-arrays. The project will investigate how many-body effects manifest themselves in reduced dimensional systems, answering questions concerning the breakdown of the Fermi Liquid Theory. A key initiative of this project will be to produce reduced-dimensional metal systems that are decoupled electronically from the underlying supporting substrate (e.g. ultra-thin oxides) and then probe their properties. The project involves "bottom-up" fabrication of metals with spatial dimensions (size and separation) down to the atomic size. The growth, structure, and morphology of these structures will be characterized on the atomic scale. Furthermore the electronic, magnetic, and chemical properties of the metals will be probed via high-resolution synchrotron photoelectron spectroscopy. Finally the experimental results will be correlated with Full Potential Linearized Augmented Plane Wave (FLAPW) and Molecular Dynamics (MD) theoretical calculations to reveal both the new features produced by the constrained dimensions and the new physics that cannot be simply addressed by band computational models. This project will increase our basic understanding of metals at the nanoscale, where novel electronic interactions and dynamic response may allow the development of a new generation of novel electronic, magnetic, photonic, and catalytic devices. From participation in the research activities of the project, both graduate and undergraduate students will be trained in the growth and characterization of nanoscale materials.

**** 非技术摘要 *** 纳米材料的电子特性与宏观材料的电子特性有很大不同。 电子的性质决定了几乎所有的物理、电子、磁性和化学性质，随着材料尺寸的减小，电子的性质变得越来越“奇异”。这项研究将使用实验和理论来揭示金属行为的量子物理学基础，因为它们的尺寸从3-D宏观材料减少到2-D表面和具有纳米厚度的薄膜，再到1-D纳米线，可以很长，但只有纳米的横截面。这些纳米级金属结构将使用允许原子维度的“旋钮”的方法制造。通过逐个原子地调整“表面体积比”，该项目将调整潜在的电子结构和物理性质。利用国家的最先进的实验技术，如扫描探针显微镜和同步加速器为基础的光电子能谱，支持纳米金属的性能将被表征。这项研究的一个关键组成部分将是相关的实验观察到的原子和电子性质的支持纳米金属与理论计算。这项研究有望增强我们对纳米尺度材料的基本理解，其中“奇异”电子相互作用允许开发新一代新型电子，磁性，光子和催化器件。研究生和本科生都将参与这个项目。他们将获得知识和学习技能，使他们能够成为学术和技术兴趣领域的富有成效的研究人员。此外，研究人员将奋进为K-12儿童和美国以其多样性及其重大的教育和经济挑战而闻名的地区的普通民众带来科学的兴奋。技术摘要 * 该奖项支持降维支撑金属电子特性的实验和理论研究。基本的主题是了解的作用，空间大小，排列和尺寸在建立随后的纳米相金属材料的电子性能发挥。 这项研究将探索金属的基本物理学（例如量子尺寸效应，多体效应，杂化），因为维度从体积减小到2-D（表面/超薄膜）到1-D（纳米线）到量子阱/纳米阵列。该项目将研究多体效应如何在降维系统中表现出来，回答有关费米液体理论崩溃的问题。该项目的一个关键举措将是生产降维金属系统，这些系统与底层支撑衬底（例如超薄氧化物）电子解耦，然后探测它们的特性。该项目涉及“自下而上”的金属制造与空间尺寸（大小和分离）下降到原子大小。这些结构的生长、结构和形态将在原子尺度上表征。此外，金属的电子，磁性和化学性质将通过高分辨率同步光电子能谱仪进行探测。最后，实验结果将与全势线性增广平面波（FLAPW）和分子动力学（MD）的理论计算相关联，以揭示约束尺寸产生的新特性和不能简单地通过能带计算模型解决的新物理。该项目将增加我们对纳米级金属的基本理解，其中新颖的电子相互作用和动态响应可能允许开发新一代新颖的电子，磁性，光子和催化器件。通过参与该项目的研究活动，研究生和本科生都将接受纳米材料生长和表征方面的培训。