Low-Dimensional Electron Systems

低维电子系统

• 批准号: 0071622
• 负责人: Arnold Dahm
• 金额: $ 29.16万
• 依托单位: Case Western Reserve University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-11-01 至 2003-10-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0071622&HistoricalAwards=false
• 关键词: Low; Dimensional; Electron; Systems

This individual investigator award is to an established scientist for a project focused on the investigation of electrons supported by a liquid helium surface and confined to one or two dimensions. It is directed towards understanding the fundamental properties of low-dimensional systems. The research consists of two parts; 1) a systematic study of electron localization induced by quantized surface waves called ripplons and 2) the transport and plasma excitations in surface electrons confined in helium-filled channels. In the first part, it is predicted that a change in the conduction from metallic to weak localization to strong localization will occur as the electric field pressing the electrons toward the surface is varied. Dephasing times in the weakly-localized regime will be measured. An understanding of the electron-ripplon interaction is important because of its potential relevance to the field of quantum computing. The study of one-dimensional surface electron systems is in its infancy, and studies have been confined to dc transport. Studies will probe the normal-mode frequencies of longitudinal (plasmons) and transverse sound modes as well as dc transport properties including localization. The undergraduate and graduate students involved in this research will learn experimental and problem solving skills that will be of use to them in their future careers.%%%This individual investigator award is to an established scientist for a fundamental study of properties of electrons confined to one and two dimensions. At low temperatures, electrons are confined to two dimensions on the surface of liquid helium. They can be further confined to one dimension by locating the helium in narrow grooves of micron-sized width. These systems are of interest because they are the simplest and cleanest examples of a one or two dimensional system. Various properties of these low dimensional electron systems have analogues in three dimensional solids, where they are more difficult to study. It is possible to vary parameters of the low dimension systems through a wider range and with more control than in the three dimensional solids. The project comprises the first attempt to probe the collective properties of one-dimensional electron systems. This study will examine localization of electrons by back scattering from quantized capillary waves (ripplons) on the helium surface. When the scattering from ripplons is made sufficiently strong by forcing an electron against the helium surface with an electric field, the electron should become localized. That is, it should become confined to a small region of micron-sized lateral dimensions. The surface will then deform to create a ripplonic polaron, an electron trapped in a small dimple in the helium surface. This interesting entity has been extensively studied by theorists. The understanding of the scattering of electrons by ripplons is particularly important, since it introduces decoherence into a new design of a quantum computer under study. The undergraduate and graduate students involved in this research will learn experimental and problem solving skills that will be of use to them in their future careers.***

这个个人研究者奖是给一个既定的科学家的一个项目，重点是调查电子支持的液氦表面和局限于一个或两个维度。 它旨在理解低维系统的基本性质。 研究包括两个部分：1）由称为ripplons的量子化表面波引起的电子局域化的系统研究和2）在氦填充通道中限制的表面电子中的输运和等离子体激发。 在第一部分中，它是预测的变化，从金属到弱本地化的强本地化的导电将发生的电场压向表面的电子是变化的。 将测量弱定域区的退相时间。 理解电子-ripplon相互作用是重要的，因为它与量子计算领域有潜在的相关性。 一维表面电子系统的研究还处于起步阶段，研究一直局限于直流输运。 研究将探测纵（等离子体激元）和横声波模式的正常模式频率以及直流传输特性，包括本地化。 参与这项研究的本科生和研究生将学习实验和解决问题的技能，这些技能将在他们未来的职业生涯中发挥作用。这个个人研究者奖是给一位对电子局限于一维和二维的性质进行基础研究的科学家。 在低温下，电子被限制在液氦表面的二维空间。 通过将氦定位在微米级宽度的窄槽中，可以进一步将它们限制在一维。 这些系统之所以令人感兴趣，是因为它们是一维或二维系统最简单、最干净的例子。 这些低维电子系统的各种性质在三维固体中具有类似物，在三维固体中它们更难以研究。 与三维固体相比，可以在更宽的范围内改变低维系统的参数，并具有更多的控制。 该项目包括首次尝试探测一维电子系统的集体性质。 本研究将探讨氦表面量子化毛细波（ripplons）后向散射的电子定位。 当用电场迫使电子撞击氦表面，使涟波子的散射足够强时，电子就会局域化。 也就是说，它应该被限制在微米级横向尺寸的小区域内。 然后，表面会变形，产生一个ripplonic极化子，一个电子被困在氦表面的一个小凹坑中。 这个有趣的实体已经被理论家广泛研究。 理解电子被涟漪散射尤其重要，因为它将退相干引入到正在研究的量子计算机的新设计中。 参与这项研究的本科生和研究生将学习实验和解决问题的技能，这些技能将在他们未来的职业生涯中对他们有用。