Quantum electron solids and interaction-driven phenomena in two- and one-dimensional systems

二维和一维系统中的量子电子固体和相互作用驱动的现象

• 批准号: 1410302
• 负责人: Jian Huang
• 金额: $ 37.5万
• 依托单位: Wayne State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-09-01 至 2019-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1410302&HistoricalAwards=false
• 关键词: Quantum; electron; solids; interaction; driven

Nontechnical: Electrons are tiny quantum mechanical objects that exist in all physical systems and most systems contain a large number of them. Understanding how electrons interact with each other and with the environment is a vital scientific subject and has played a critical role in advancing modern science and technologies. Analogous to water, electrons manifest both gaseous states at high temperatures and liquid states at low temperatures. Another form is a solid state which was predicted but never observed. To obtain evidence of this solid state of electrons is not only important in understanding how the most basic force can radically affect the quantum states, but also allows scientists to develop remarkable future quantum electronics and spintronics. These energy sustainable systems are fundamentally important to nature. With greatly improved semiconductor technologies, a novel type of semiconductors of ultra-high purity has become available as a result of a recent breakthrough and preliminary results have been recently obtained as evidence of a genuine quantum electron solid. This project utilizes such devices to perform experiments with the most advanced scientific tools: nanofabrication and ultra-low temperature physics. The goal is to capture the direct evidence for the quantum mechanical mechanisms in the dynamical properties. This project supports the education of one Ph.D. student in pursuing discovery and advanced technologies, and allows the group to conduct outreach activities with local high schools. Technical: Remarkable new quantum phenomena, such as the even-denominator Fractional Quantum Hall Effect and Topological Insulators, emerge in response to strong inter-particle Coulomb interaction. However, the most prominent interaction-driven effect, Wigner crystallization of electrons, has not been well established. This fascinating quantum matter (with spin ordering) is not only paramount to fundamental science, but also important for future applications including quantum electronics and spintronics. For a long time, experimental effort was hindered because most devices contain a high level of unwanted disorder which overwhelms the interaction effect at low electron densities. Since 2003, breakthroughs have been made in providing ultra-high quality two-dimensional electron systems in GaAs semiconductor field-effect-transistors. Recent achievement with the measurement of ultrahigh purity GaAs field-effect transistors (named HIGFET) has led to the observation of a genuine WC. Moreover, the preliminary results also point to possible quantum pinning/depinning mechanisms that are not understood. This project utilizes these types of devices with record low electron densities to perform transport experiments at mK temperatures. The goal is to verify the quantum nature of the dynamical properties well below the classical limits. Various techniques such varying temperature, density, and interaction are adopted to study the phase boundaries. AC+DC excitation technique is utilized to directly probe the collective, large-scale quantum tunneling in a Wigner Crystal. This project supports the education of one Ph.D. student in pursuing discovery and in learning advanced technologies, which are indispensable for excellent training in pursuing scientific careers.

非技术性：电子是存在于所有物理系统中的微小量子力学对象，大多数系统都包含大量电子。了解电子如何相互作用以及与环境的相互作用是一个重要的科学课题，并在推动现代科学和技术方面发挥了关键作用。与水类似，电子在高温下表现为气态，在低温下表现为液态。另一种形式是一种被预测但从未被观察到的固态。获得这种电子固态的证据不仅对理解最基本的力如何从根本上影响量子态很重要，而且还使科学家能够开发出非凡的未来量子电子学和自旋电子学。这些能源可持续系统对自然至关重要。 随着半导体技术的极大改进，由于最近的突破，一种新型的超高纯度半导体已经成为可能，并且最近已经获得了初步结果作为真正的量子电子固体的证据。该项目利用这些设备进行最先进的科学工具实验：纳米纤维和超低温物理学。我们的目标是捕捉动力学性质中量子力学机制的直接证据。该项目支持一名博士的教育。该组织的宗旨是鼓励学生追求发现和先进技术，并允许该组织与当地高中开展外展活动。技术支持：在强库仑相互作用下，出现了一些新的量子现象，如偶分母分数量子霍尔效应和拓扑绝缘体。 然而，最突出的相互作用驱动效应，电子的维格纳结晶，还没有得到很好的建立。这种迷人的量子物质（具有自旋有序性）不仅对基础科学至关重要，而且对未来的应用也很重要，包括量子电子学和自旋电子学。很长一段时间以来，实验工作受到阻碍，因为大多数器件包含高水平的不必要的无序，这使得在低电子密度下的相互作用效应无效。自2003年以来，在GaAs半导体场效应晶体管中提供超高质量二维电子系统方面取得了突破性进展。最近的成就与测量的高纯度砷化镓场效应晶体管（命名为高场效应晶体管）导致观察到一个真正的WC。此外，初步的结果还指出可能的量子钉扎/脱钉扎机制还不清楚。该项目利用这些类型的设备与创纪录的低电子密度在mK温度下进行传输实验。我们的目标是验证量子性质的动力学性能远低于经典的限制。采用不同的技术，如变化的温度，密度，和相互作用来研究相边界。 利用AC+DC激发技术直接探测维格纳晶体中的集体大尺度量子隧穿。 该项目支持一名博士的教育。学生追求发现和学习先进技术，这是追求科学事业的优秀培训所不可或缺的。