High-Sensitivity Thermodynamic Measurements of Interacting Disordered Quantum Hall Systems

相互作用的无序量子霍尔系统的高灵敏度热力学测量

• 批准号: 0404445
• 负责人: Hong-Wen Jiang
• 金额: $ 32.7万
• 依托单位: University of California-Los Angeles
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-04-01 至 2008-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0404445&HistoricalAwards=false
• 关键词: Sensitivity; Thermodynamic; Measurements; Interacting; Disordered

This experimental condensed matter physics project involves high-sensitivity thermodynamic measurements of interacting disordered semiconductor heterostructures. The thermodynamic measurements provide probes the many-body ground state properties of these devices. Specifically, two high sensitivity measurements are planned. First, spatial distribution of the thermodynamic compressibility of a two-dimensional electron layer will be mapped out using a cryogenic scanning tunneling microscope. Second, orbital and spin magnetization of a strongly interacting hole device will be measured using a torsion magnetometer. Emphasis will be on how the disorder can quantitatively and qualitatively alter the many-body ground state properties. Several outstanding questions will be addressed concerning the nature of the insulating and the metallic states in two-dimensions at zero magnetic field, the evolution of these phases to the quantum Hall states as the magnetic field is increased, and the spin states of an interacting system with disorders. The results anticipated from these experiments are expected to provide a better understanding of the effects of disorder on correlated low-dimensional semiconductor devices. This advanced basic knowledge should have broader impacts on the development of the next generation of semiconductor devices for high-speed communications, signal processing, imaging, and detection. For example, the new technological areas such as semiconductor-based quantum computation, quantum communications, and spintronics are known to depend heavily on this kind of knowledge basis. In addition, the high sensitivity measurement techniques developed in this research can be used beyond the semiconductor devices. Thermodynamic properties of a board spectrum of small-scale condensed matter materials can be potentially studied with these technical tools. Finally, the hands-on research will give graduate students as well as undergraduate students an excellent preparation for careers in academe, industry, and government.This experimental condensed matter physics involves high-sensitivity thermodynamic measurements of semiconductor heterostructures. These devices are very similar to those widely used on high-speed electronics in information processing. Unlike the more conventional electrical measurements, the thermodynamic measurements provide means to understand the fundamental energy configuration of these electronic devices. Two specific experiments will be conducted. A low-temperature scanning tunneling microscope will be used to map out the local electrical compressibility of an electron device. The tiny magnetization of a layer of charge carriers will be measured by an ultra-sensitive torsion magnetometer. The results anticipated from these experiments are expected to lead fundamental insights in the physics of these semiconductor devices; particularly the basic questions that cannot be answered by the conventional transport measurements. This basic knowledge should have impact on next generation of semiconductor devices for high-speed communications, signal processing, imaging, and detection. For example, the new technological areas such as semiconductor-based quantum computation, quantum communications, and spintronics are known to depend heavily on this kind of knowledge basis. In addition, the high sensitivity measurement techniques developed in this research can be used beyond the semiconductor devices. Thermodynamic properties of a board spectrum of small-scale condensed matter materials can be potentially studied with these technical tools. The hands-on research will give involved graduate students as well as undergraduate students an excellent preparation for careers in academe, industry, and government.

这个实验凝聚态物理项目涉及相互作用的无序半导体异质结构的高灵敏度热力学测量。热力学测量为探测这些器件的多体基态性质提供了依据。具体而言，计划进行两次高灵敏度测量。首先，利用低温扫描隧道显微镜绘制出二维电子层热力学压缩系数的空间分布。其次，强相互作用空穴器件的轨道和自旋磁化强度将使用扭转磁力计测量。重点将放在如何无序可以定量和定性地改变多体基态性质。几个悬而未决的问题将得到解决的绝缘和金属状态在二维零磁场的性质，这些阶段的量子霍尔态的磁场增加的演变，和自旋状态的相互作用系统的障碍。从这些实验预期的结果，预计将提供一个更好的理解相关的低维半导体器件上的无序的影响。这些先进的基础知识应该对下一代高速通信、信号处理、成像和检测半导体器件的开发产生更广泛的影响。例如，新的技术领域，如基于光子晶体的量子计算，量子通信和自旋电子学，都严重依赖于这种知识基础。此外，本研究所发展之高灵敏度量测技术，可应用于半导体元件之外。 利用这些技术工具，可以潜在地研究小尺度凝聚态材料的板谱的热力学性质。最后，实践研究将为研究生和本科生在计算机，工业和政府的职业生涯做好准备。这个实验凝聚态物理涉及半导体异质结构的高灵敏度热力学测量。这些设备与信息处理中高速电子设备上广泛使用的设备非常相似。与更传统的电气测量不同，热力学测量提供了理解这些电子设备的基本能量配置的手段。将进行两个具体实验。低温扫描隧道显微镜将用于绘制出电子器件的局部电压缩性。 电荷载体层的微小磁化将由超灵敏的扭转磁力计测量。从这些实验中预期的结果预计将导致这些半导体器件的物理学的基本见解，特别是传统的传输测量无法回答的基本问题。这些基础知识将对下一代高速通信、信号处理、成像和检测半导体器件产生影响。例如，新的技术领域，如基于光子晶体的量子计算，量子通信和自旋电子学，都严重依赖于这种知识基础。此外，本研究所发展之高灵敏度量测技术，可应用于半导体元件之外。利用这些技术工具，可以潜在地研究小尺度凝聚态材料的板谱的热力学性质。实践研究将为参与研究的研究生和本科生提供在工业，工业和政府职业生涯的良好准备。