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

非技术：电子是微小的量子力学对象，存在于所有物理系统中，大多数系统包含大量电子。了解电子如何相互作用以及如何与环境相互作用是一门重要的科学课题，并在推进现代科学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。另一种形式是固态，它被预测但从未被观察到。获得这种固体电子状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，而且还允许科学家开发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。随着半导体技术的巨大进步，一种新型的超高纯度半导体已经成为可能，最近的突破和初步结果已经获得了真正的量子电子固体的证据。本项目利用这些设备与最先进的科学工具：纳米制造和超低温物理进行实验。目标是捕捉动力学性质中量子力学机制的直接证据。该项目支持一名追求发现和先进技术的博士生的教育，并允许该小组与当地高中开展外展活动。技术：随着强粒子间库仑相互作用的出现，出现了显著的新量子现象，如偶数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，尚未得到很好的确立。这种令人着迷的量子物质（具有自旋有序）不仅对基础科学至关重要，而且对包括量子电子学和自旋电子学在内的未来应用也很重要。长期以来，实验工作受到阻碍，因为大多数器件含有高水平的不必要的无序，这压倒了低电子密度下的相互作用效应。自2003年以来，在GaAs半导体场效应晶体管中提供超高质量的二维电子系统方面取得了突破。最近在测量超高纯度砷化镓场效应晶体管（称为HIGFET）方面取得的成就导致了对真正WC的观察。此外，初步结果还指出了尚未理解的可能的量子钉钉/脱钉机制。本项目利用这些类型的低电子密度器件在mK温度下进行输运实验。目标是验证远低于经典极限的动力学性质的量子性质。采用了各种技术，如变温度、变密度、变相互作用等来研究相界。利用交流+直流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生追求发现和学习先进技术的教育，这是追求科学事业的优秀训练所必不可少的。

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.