Thermodynamic Measurements of Interacting Disordered Quantum Hall Systems

Jiang 0071969本研究主要是对无序半导体异质结构的热力学测量。 在低维量子系统中，由于无序的存在，强关联的问题变得更加困难。 特别是，相互作用的无序量子霍尔器件的热力学性质仍然知之甚少。 一个高密度的GaAs/AlGaAs量子阱结构的两个填充的子带，以及一个p型单异质结构的高度相关的孔将用于调查。 压缩性将通过使用场穿透技术来探测内部相互作用能来测量。 将通过扭转磁力计测量磁化强度，以确定不同电子相位下的自旋极化。 将按照从早期运输研究中获得的“路线图”探索各种物理制度。 电控门将用于改变密度，改变屏蔽特性，并改变无序的空间相关性。 当代的问题，如零场二维金属-绝缘体过渡的性质，它与量子霍尔效应的关系，以及两组分系统中朗道能级相互作用的后果，将得到解决。 本项目也将为固态电子学领域的研究生和本科生提供一个很好的培训。 事实上，半导体器件制造和表征方面的工作与半导体电子工业目前正在进行的工作密切重叠。本计画主要研究在无序与载子交互作用下，薄层状半导体结构的热性质。 类似的结构目前用于高速电子和光电子技术。 由于无序和相互作用之间错综复杂的相互作用，这些先进设备的属性是不可预测的，有时甚至看起来很神秘。 拟议的实验研究了几个知之甚少的量子电子相的热性质，通过使用几个高灵敏度的测量技术。 其主要目的是更好地理解这些阶段的基本物理原理和所表现出的丰富效应。 更好的理解反过来可以为设计下一代电子产品提供基础。 从所提出的实验中获得的概念可以应用于一些更复杂的凝聚态系统。 关于电子自旋的工作可能会对未来量子计算和量子通信的量子信息处理系统的发展产生潜在的影响。本项目也将为固态电子学领域的研究生和本科生提供一个很好的培训。 事实上，半导体器件制造和表征方面的工作与半导体电子工业目前正在进行的工作密切重叠。

Jiang0071969This research is focused on the thermodynamic measurements of interacting disordered semiconductor heterostructures. The problem of strong correlations, in low-dimensional quantum systems, is made more difficult by the presence of disorder. Particularly, the thermodynamic properties of interacting disordered quantum Hall devices is still poorly understood. A high density GaAs/AlGaAs quantum well structure with two populated subbands as well as a p-type single-heterostructure with highly correlated holes will be used for the investigations. Compressibility will be measured by using a field-penetration technique to probe the internal interaction energy. Magnetization will be measured by a torsional magnetometer to determine the spin polarization at different electronic phases. Various physical regimes will be explored following the "road-maps" obtained from early transport studies. Electrically controlled gates will be used to vary the density, to alter the screening properties, and to change the spatial correlation of the disorder. Contemporary issues, such as the nature of the zero-field 2D metal-insulator transition, its relation to quantum Hall effect, and consequences of Landau level interactions in two-component systems, will be addressed. This project will also provide an excellent training for graduate and undergraduate students in this program for solid state electronics field. In fact, the semiconductor device fabrication and characterization aspects of the work overlaps closely with what is going on right now in semiconductor electronics industry.%%%This project is concentrated on the study of thermal properties of thin-layered semiconductor structures in the presence of both disorder and carrier interaction. Similar structures are currently used for high-speed electronics and opto-electronics technologies. Due to the intricate interplay of disorder and interaction, the properties of these advanced devices are less predictable, and sometimes even appear to be mysterious. The proposed experiments study the thermal properties of several poorly understood quantum electronic phases by using several high-sensitivity measurement techniques. The main objective is to establish a better understanding on the underlying physical principle of these phases and the wealth of effects exhibited. The better understandings can, in turn, provide a basis for designing the next generation of electronics. The concepts obtained from the proposed experiments can be applied to some of the more complex condensed matter systems. The work concerning electron spins could potentially have impact on the development of future quantum information processing systems for quantum computing and quantum communications. This project will also provide an excellent training for graduate and undergraduate students in this program for solid state electronics field. In fact, the semiconductor device fabrication and characterization aspects of the work overlaps closely with what is going on right now in semiconductor electronics industry.