Cooperative Effects Of Impurities On Electron Transport In Low-Dimensional Nanostructures

杂质对低维纳米结构中电子传输的协同效应

• 批准号: 0706654
• 负责人: Michael Fogler
• 金额: $ 24万
• 依托单位: University of California-San Diego
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-09-15 至 2010-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0706654&HistoricalAwards=false
• 关键词: Cooperative; Effects; Impurities; Electron; Transport

TECHNICAL SUMMARY:This award supports theoretical research and education in condensed matter physics on the subject of transport in quasi-one-dimensional systems. Investigations will be undertaken into transport properties of ultra-thin wires, e.g. carbon nanotubes, semiconductor nanowires, polymer nanofibers, graphene ribbons. Research is motivated by the fact that such systems often show distinctly unconventional dependences on temperature, external fields, and other experimentally tunable parameters, as well as large sample-to-sample variability. A program of theoretical investigations is undertaken towards providing theoretical descriptions and computer simulations to provide understanding the physics behind such anomalies. The transport characteristics of primary importance are ensemble-averaged conductivity, its dependence on intrinsic and external parameters, its statistical distribution, and its temporal and spatial fluctuations (noise). The special focus of the proposed research is to elucidate the role of cooperative impurity effects and Coulomb interactions at the root of the observed transport laws. Additionally, some relatively new phenomena that arise from a combined action of multiple impurities in systems with a finite concentration of dopants and defects are addressed. The PI will investigate the degree to which these phenomena are pervasive in such one-dimensional and quasi-one-dimensional conductors. It is expected that the phenomena originate from the tight geometric constraints imposed on the current pathways by the reduced dimensionality and from strong electron-electron interactions typical of these systems.This research is undertaken at an institution with an ethnically diverse student body, allowing the PI to develop components of the research program that can be conducted in a close collaboration with a team of talented and ethnically diverse graduate and undergraduate students. The research engagement allows students to gain technical knowledge and problem-solving skills. The undergraduate students particularly have opportunities to participate in cutting-edge research in an environment not otherwise available. Beyond this, the PI extends the impact of the program with outreach activities at summer science camps for area high school students.NON-TECHNICAL SUMMARY:This award supports theoretical research and education in condensed matter physics on how electric charge moves through systems of ultra-thin wire-like materials that are part of the developments in nanotechnology. The scientific questions addressed in this proposal involve the peculiar and unusual properties that develop with extreme miniaturization of electronic components that are the core elements of nanotechnology. Particular examples of the extreme miniaturization include a number of structures that are long but very narrow and are termed nanowires. Nanowires may be constructed from a variety of materials such as metals, polymers or semiconductors. Independent of many specifics, there are universal characteristics of transport in nanowires that have amorphous structure, i.e. noncrystalline, at the molecular and atomic level. Understanding the origins of properties that are similar when the materials are extremely different is of keen interest for future technological applications being considered by a broad community of researcher in pure and applied sciences. Reliable answers to such questions that arise from unconventional properties of electrical and heat flow in nanostructures is fundamental to most future applications on nanotechnology. This research is undertaken at an institution with an ethnically diverse student body, allowing the PI to develop components of the research program that can be conducted in a close collaboration with a team of talented and ethnically diverse graduate and undergraduate students. The research engagement allows students to gain technical knowledge and problem-solving skills. The undergraduate students particularly have opportunities to participate in cutting-edge research in an environment not otherwise available. Beyond this, the PI extends the impact of the program with outreach activities at summer science camps for area high school students.

该奖项支持凝聚态物理学中准一维系统传输问题的理论研究和教育。 将对超薄导线的输运性质进行研究，例如碳纳米管，半导体纳米线，聚合物纳米纤维，石墨烯带。研究的动机是这样一个事实，即这样的系统往往表现出明显的非常规依赖于温度，外部场，和其他实验可调参数，以及大的样品到样品的变化。一个理论研究计划是对提供理论描述和计算机模拟，以提供理解这种异常背后的物理。最重要的传输特性是系综平均电导率，它对内部和外部参数的依赖性，它的统计分布，以及它的时间和空间波动（噪声）。建议的研究的特别重点是阐明合作杂质效应和库仑相互作用的作用，在所观察到的传输定律的根源。此外，一些相对较新的现象，所产生的多种杂质在系统中与有限浓度的掺杂剂和缺陷的组合作用得到解决。PI将调查这些现象在这种一维和准一维导体中普遍存在的程度。预计这些现象起源于由降维对电流路径施加的严格几何约束以及这些系统典型的强电子-电子相互作用。这项研究是在一个具有种族多样性学生的机构进行的，允许PI开发研究计划的组成部分，这些组成部分可以与一个有才华和种族多样性的研究生团队密切合作进行和本科生。研究参与使学生获得技术知识和解决问题的能力。 本科生特别有机会在无法获得的环境中参与前沿研究。除此之外，PI还通过为地区高中生举办的暑期科学夏令营活动扩大了该计划的影响。非技术性总结：该奖项支持凝聚态物理学的理论研究和教育，即电荷如何通过纳米技术发展的一部分超薄线状材料系统移动。该提案中提出的科学问题涉及到随着作为纳米技术核心要素的电子元件的极端微型化而发展的特殊和不寻常的性质。 极端小型化的具体实例包括许多长但非常窄的结构，称为纳米线。纳米线可以由多种材料构成，例如金属、聚合物或半导体。独立于许多细节，在分子和原子水平上具有非晶结构（即非结晶）的纳米线中存在普遍的输运特性。了解当材料极其不同时相似性质的起源对于纯科学和应用科学研究人员广泛考虑的未来技术应用具有浓厚的兴趣。可靠的答案，从纳米结构中的电流和热流的非常规性能所产生的这些问题是最基本的未来应用纳米技术。这项研究是在一个具有种族多样性的学生团体的机构进行的，使PI能够开发研究计划的组成部分，这些研究计划可以与一个有才华和种族多样性的研究生和本科生团队密切合作进行。研究参与使学生获得技术知识和解决问题的能力。 本科生特别有机会在无法获得的环境中参与前沿研究。除此之外，PI还通过为地区高中生举办的暑期科学夏令营的外联活动扩大了该计划的影响。