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

技术综述：该奖项支持关于准一维系统中输运问题的凝聚态物理的理论研究和教育。将对超细导线的传输特性进行研究，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，即这样的系统通常表现出对温度、外场和其他可通过实验调节的参数的明显的非常规依赖，以及大的样本到样本的可变性。为了提供理论描述和计算机模拟来理解这些反常现象背后的物理原因，进行了一系列的理论研究。最重要的输运特征是集合平均电导率、它对内部和外部参数的依赖、它的统计分布以及它的时间和空间起伏(噪声)。这项研究的重点是阐明协同杂质效应和库仑相互作用在所观察到的输运定律中的作用。此外，还讨论了在具有有限浓度的掺杂和缺陷的系统中由于多种杂质的联合作用而出现的一些相对较新的现象。PI将调查这些现象在这种一维和准一维导体中的普遍程度。预计这些现象源于降维对当前路径施加的严格几何约束，以及这些系统典型的强烈电子-电子相互作用。这项研究在一所学生群体多元化的机构进行，允许PI开发研究计划的组成部分，可以与才华横溢、种族多元化的研究生和本科生团队密切合作进行。研究活动使学生能够获得技术知识和解决问题的技能。本科生尤其有机会在其他方面无法获得的环境中参与尖端研究。除此之外，PI还通过在夏季科学夏令营为地区高中生开展外联活动来扩大该计划的影响。非技术概述：该奖项支持凝聚态物理的理论研究和教育，即电荷如何在超细线状材料系统中运动，这些材料是纳米技术发展的一部分。这项提案中涉及的科学问题涉及随着作为纳米技术核心元素的电子元件的极端微型化而产生的特殊和不同寻常的特性。极端小型化的具体例子包括一些长但非常窄的结构，被称为纳米线。纳米线可以由各种材料制成，例如金属、聚合物或半导体。与许多细节无关，在分子和原子水平上，具有非晶态结构的纳米线具有普遍的输运特征。当材料非常不同时，了解相似性质的起源对于理论科学和应用科学的广泛研究人员正在考虑的未来技术应用具有浓厚的兴趣。对纳米结构中电流和热流的非传统特性产生的这些问题的可靠答案，是未来大多数纳米技术应用的基础。这项研究是在一个学生群体种族多元化的机构进行的，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的、种族多元化的研究生和本科生团队密切合作进行。研究活动使学生能够获得技术知识和解决问题的技能。本科生尤其有机会在其他方面无法获得的环境中参与尖端研究。除此之外，PI还通过在地区高中生的夏季科学夏令营开展外联活动来扩大该计划的影响。

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.