NIRT: Coherence and Correlations in Electronic Nanostructures

技术说明：该奖项是根据纳米科学与工程招标（NSF 04-043）收到的NIRT类别提案授予的。材料研究部、化学部、数学科学部和物理部为这种理论和计算研究和教育提供支持。本项目聚焦于相干和相关之间的相互作用，这是量子纳米科学的一个核心问题。相干性产生干涉效应，而相关性是由于电子相互排斥而产生的电子相互之间的组织。两者之间的相互作用尤其发生在纳米尺度上：量子干涉很强，因为系统小于消相长度；由此产生的密度调制产生了强电子-电子（e-e）相互作用效应。这些效应可以被调节，为固态量子系统提供前所未有的控制水平。pi将研究从纳米到毫米的模型和现实系统中的量子相干性和电子-电子相互作用，目的是阐明这两种效应在纳米结构中的相互作用。这项工作将为评估这些新兴纳米技术的实际相关性以及对当前化学和物理学中最深奥的主题之一的基础研究提供所需的知识库。ppi将集中于三个具体目标：单分子的电导：pi计划对候选分子进行计算研究，寻找开关、整流和负微分电阻存在的证据。理论和计算方法将进一步发展，包括一种优化的有效势方法和一种计算工作量与原子数量成线性比例的方法。pi计划解决电子通过分子传递的相互作用效应的基本问题。低密度点和线：低电子密度增强了相关效应。使用量子蒙特卡罗方法，pi将计算圆形和不规则量子点的性质，特别注意局部顺序的签名。在量子线中，他们计划研究Matveev情景中的“0.7平台”。量子点作为量子杂质：量子点与引线的相互作用，例如，带有读出电极的量子比特，可以映射到量子杂质问题。pi将从描述量子点-铅系统中介观波动的作用开始。pi将研究多通道杂质问题的实现，以及多量子点系统。本科生、研究生和博士后研究人员将参与该项目的各个方面。除了杜克大学的核心团队外，该项目还涉及另外三名高级研究人员，分别来自康奈尔大学、阿贡国家实验室和法国。它建立了大学间、大学-国家实验室和国际合作。该项目包括两个扩展部分：(1)参与杜克大学全国认可的项目，让来自代表性不足群体的本科生参与夏季研究。(2)参加高中教师暑期化学前沿课题讲座项目。非技术解释：该奖项是根据纳米科学与工程招标（NSF 04-043）收到的NIRT类别提案颁发的。材料研究部、化学部、数学科学部和物理部为该奖项提供支持。这个理论和计算研究项目的重点是电子所显示的基本现象，特别是在纳米尺度的原子结构中，如量子点和量子线。这项研究的核心是电子的波动性质和它们之间的相互作用之间的相互作用。原子和大分子的纳米级结构可以为研究这种相互作用提供一个可控的环境。由此产生的效应及其操作对于阐明量子力学世界的本质具有重要的科学意义，也可能有助于为未来的纳米级电子设备提供操作原理。本科生、研究生和博士后研究人员将参与该项目的各个方面，为培养下一代理论和计算科学家做出贡献。除了杜克大学的核心团队外，该项目还涉及另外三名高级研究人员，分别来自康奈尔大学、阿贡国家实验室和法国。它建立了大学间、大学-国家实验室和国际合作。该项目包括两个扩展部分：(1)参与杜克大学全国认可的项目，让来自代表性不足群体的本科生参与夏季研究。(2)参加高中教师暑期化学前沿课题讲座项目。

TECHNICAL EXPLANATION:This award is made on a NIRT category proposal received in response to the Nanoscale Science and Engineering solicitation, NSF 04-043. The Division of Materials Research, the Chemistry Division, the Division of Mathematical Sciences, and the Physics Division contribute support for this theoretical and computational research and education. This project is focused on the interplay between coherence and correlation, which is a central issue in quantum nanoscience. Coherence gives rise to interference effects, while correlation is the organization of electrons with respect to each other that arises as a consequence of their mutual repulsion. The interplay between the two occurs particularly at the nanoscale: Quantum interference is strong because the system is smaller than the dephasing length; the resulting density modulation gives rise to strong electron-electron (e-e) interaction effects. These effects can be tuned, providing in solid-state quantum systems an unprecedented level of control.The PIs will study quantum coherence and electron-electron interactions in both model and realistic systems from nm to mm with an aim to elucidate the interplay between these two effects in nanostructures. The work will contribute to the knowledge base needed to evaluate the practical relevance of these nascent nanotechnologies and to fundamental research on one of the deepest topics in current chemistry and physics. The PIs will concentrate on three specific thrusts:1. Conductance of single molecules: The PIs plan computational investigations of candidate molecules searching for evidence of switching, rectification, and the presence of negative differential resistance. Theoretical and computational methods will be further developed, including an optimized effective potential approach and a method for which computational effort scales linearly with the number of atoms. The PIs plan to tackle the fundamental issue of interaction effects in electron transport through molecules.2. Low density dots and wires: Correlation effects are enhanced by low electron density. Using quantum Monte Carlo methods, the PIs will calculate properties of both circular and irregular quantum dots, paying particular attention to signatures of local order. In quantum wires, they plan to investigate the Matveev scenario for the "0.7 plateau."3. Quantum dots as quantum impurities: The interaction of a quantum dot with a lead, as in, for example, a qubit with a readout electrode, can be mapped onto quantum impurity problems. The PIs will begin by characterizing the role of mesoscopic fluctuations in quantum dot-lead systems. The PIs will study realizations of multichannel impurity problems, as well as systems of multiple quantum dots.Undergraduate, graduate, and postdoctoral researchers will be involved in all aspects of this project. Beyond the core team at Duke, the project involves three other senior researchers, one each at Cornell, at Argonne National Lab, and in France. It builds inter-university, university-national lab, and international collaborations. This project incorporates two outreach components: (1) Participation in Duke's nationally recognizedprograms for involving undergraduates from underrepresented groups in summer research. (2) Participation in a program of summer lectures for high school teachers on frontier topics in chemistry.NON-TECHNICAL EXPLANATION:This award is made on a NIRT category proposal received in response to the Nanoscale Science and Engineering solicitation, NSF 04-043. The Division of Materials Research, the Chemistry Division, the Division of Mathematical Sciences, and the Physics Division contribute support for this award. This theoretical and computational research project is focused on fundamental phenomena displayed by electrons particularly in nanoscale structures of atoms such as quantum dots and quantum wires. Central to this study is the interplay between the wave nature of electrons and the interactions between them. Nanoscale structures of atoms and large molecules may provide a controlled environment to study this interplay. The effects that arise and their manipulation are of fundamental scientific interest in elucidating the nature of the quantum mechanical world and may also help provide the operating principles for future nanoscale electronic devices. Undergraduate, graduate, and postdoctoral researchers will be involved in all aspects of this project contributing to the training of the next generation theoretical and computational scientists. Beyond the core team at Duke, the project involves three other senior researchers, one each at Cornell, at Argonne National Lab, and in France. It builds inter-university, university-national lab, and international collaborations. This project incorporates two outreach components: (1) Participation in Duke's nationally recognizedprograms for involving undergraduates from underrepresented groups in summer research. (2) Participation in a program of summer lectures for high school teachers on frontier topics in chemistry.