Spin, Heat and Charge Transport in Quantum Hall Edge Modes

量子霍尔边缘模式中的自旋、热和电荷传输

• 批准号: 1206016
• 负责人: Amir Yacoby
• 金额: $ 52万
• 依托单位: Harvard University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-07-01 至 2016-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1206016&HistoricalAwards=false
• 关键词: Spin; Heat; Charge; Transport; Quantum

****Technical Abstract****This research project will investigate spin, heat and charge transport in quantum Hall edge modes. Already in the integer quantum Hall regime once edge reconstruction occurs, correlated electron physics described by Luttinger liquid theory is needed in order to properly describe edge mode characteristics. In the fractional quantum Hall regime edge reconstruction is expected to produce both charged and neutral excitations that result from the interplay between confinement, Coulomb repulsion and disorder. A renewed interest in quantum Hall systems also arises due to the prospects of using such systems for topological quantum computing. Furthermore, in recent years, edge mode physics has also immerged in other material systems known as topological insulators even in the absence of an external magnetic field. Leading examples of intriguing edge mode physics in these systems are the quantized spin Hall effect and the anomalous quantized Hall insulator. Three approaches will be used in this project: cleaved edge overgrowth for sharp edges, laterally defined edges and suspended graphene. The experimental tools developed here for studying edge mode physics in the quantized Hall regime will offer new approaches for exploring edge mode physics in this new class of materials. This project will assess the possible technological use of topologically protected edge modes for dissipationless transfer of information in solid state devices. The research will be incorporated into our new graduate program that will be centered on the "fundamental properties of materials and their applications" as well as into our undergraduate curriculum addressing the "principles of scientific inquiry". ****Non Technical Abstract****Microelectronic circuitry changed our lives. One of the growing challenges, however, in this field is the dissipation of energy or heat production due to the flow of electricity within such devices. These challenges call for new approaches for carrying information across microscopic dimensions. This project seeks to use other properties of electrons such as their intrinsic angular momentum, known as spin, as opposed to their charge, for carrying information. Electros move in circles when subject to an external magnetic field. In clean samples such circular motion prevents electricity from flowing in the bulk from one side of the sample to the other. However, near the boundaries of a sample this circular motion leads to skipping orbits which allow electrons to traverse the length of the sample without dissipation. In addition to their charge, electrons also carry spin and heat. Under unique conditions that result from the interactions between neighboring electrons, the edge modes at the boundary can carry heat and spin currents without carrying any charge current. Such neutral modes offer intriguing possibilities for carrying information without involving the charge of the carries. This project explores the properties of such edge modes in high purity semiconductors and will assess their utility in future applications. Participating students are trained in technological areas that are front and center in the nanoelectronics industry including nanofabrication, electrical measurement and data acquisition. Furthermore, by incorporating the research topics into the undergraduate and graduate curriculum, this project will prepare the next generation of scientists for future challenges in nanoelectronics and their applications.

* 技术摘要 * 本研究项目将研究量子霍尔边缘模式中的自旋、热和电荷输运。已经在整数量子霍尔制度，一旦边缘重建发生，相关的电子物理描述的Luttinger液体理论是必要的，以正确地描述边缘模式的特点。在分数量子霍尔制度的边缘重建预计将产生带电和中性的激发，从禁闭，库仑排斥和无序之间的相互作用的结果。量子霍尔系统的新的兴趣也出现了由于拓扑量子计算使用这样的系统的前景。 此外，近年来，边缘模式物理学也沉浸在其他被称为拓扑绝缘体的材料系统中，即使在没有外部磁场的情况下。这些系统中有趣的边缘模式物理的主要例子是量子化自旋霍尔效应和反常量子化霍尔绝缘体。在这个项目中将使用三种方法：切割边缘过度生长的尖锐边缘，横向定义的边缘和悬浮的石墨烯。在这里开发的实验工具，用于研究边缘模式物理的量子化霍尔制度将提供新的方法，探索边缘模式物理在这类新的材料。这个项目将评估拓扑保护的边缘模式在固态设备中无耗散传输信息的可能技术用途。这项研究将被纳入我们新的研究生课程，将集中在“材料的基本特性及其应用”，以及到我们的本科课程解决“科学探究的原则”。* 非技术摘要 * 微电子电路改变了我们的生活。然而，在该领域中，日益增长的挑战之一是由于这种设备内的电流而导致的能量耗散或热产生。这些挑战需要新的方法来携带跨微观维度的信息。这个项目试图利用电子的其他属性，如它们的固有角动量，称为自旋，而不是它们的电荷，来携带信息。当受到外部磁场的作用时，电子作圆周运动。在干净的样品中，这种圆周运动防止电流从样品的一侧流向另一侧。然而，在样品的边界附近，这种圆周运动导致跳过轨道，这允许电子穿过样品的长度而没有耗散。除了电荷，电子还携带自旋和热量。在由相邻电子之间的相互作用产生的独特条件下，边界处的边缘模式可以携带热量和自旋电流，而不携带任何电荷电流。这种中性模式提供了有趣的可能性，可以携带信息而不涉及载体的电荷。该项目探索高纯度半导体中此类边缘模式的特性，并将评估它们在未来应用中的实用性。参与的学生在纳米电子行业的前沿和中心技术领域接受培训，包括纳米纤维，电气测量和数据采集。此外，通过将研究课题纳入本科和研究生课程，该项目将为下一代科学家在纳米电子学及其应用的未来挑战做好准备。