Experimental Investigation of Delocalization and Phase Diagram in Quantum Hall Systems

小行星9705439 这个实验研究项目的重点是量子霍尔效应机制中的二维电子气，特别是相图和受无序影响的局域-离域转变。 门控GaAs/AlGaAs器件将被用来控制实验系统的有效无序。 将进行强磁场输运实验以研究磁场诱导的 离域转变，并确定在无序磁场平面的相图。 边缘态隧穿光谱将用于探测各种电子相的微观性质和低能激发。 这个实验研究项目致力于研究二维平面区域中导电电子系统的基本性质。 在低温和高磁场下，这样一组受限的电子表现出一组非常不寻常的特征，这对那些希望测试和扩展晶体固体中电子基本理论的理论家来说是很有意义的。 改进后的理论可以更有把握地应用于广泛的金属和半导体，这些金属和半导体在微电子学和其他技术中具有重要意义。 中的实验 这 项目的重点是“金属-绝缘体”过渡，这是已经观察到的，特别是它是如何与电子环境中的无序联系起来的。 一方面，这些实验将提供有关低温下电子在受限层中相互作用的新的基本信息。 另一方面，在这些实验中使用的器件结构 是 使用的类似 在 先进微电子 气体技术中的设备。 这项研究将涉及学生谁将在物理领域得到良好的训练，也将获得熟悉与半导体器件技术，ND谁将得到良好的训练 为 工业就业， 各国政府， 或教育。 ***

9705439 Jiang This experimental research project focuses on the 2-D electron gas in the quantum Hall effect regime, specifically on the phase diagram and a localization-delocalization transition as afffected by disorder . Gated GaAs/AlGaAs devices will be used to gain control of the effective disorder of the experimental system. High magnetic field transport experiments will be carried out to study the magnetic-field-induced delocalization transition and to determine the phase diagram in the disorder-magnetic field plane. Edge-state tunneling spectroscopy will be used to probe microscopic properties and low-energy excitation of various electronic phases. %%% This experimental research project is devoted to basic properties of a conducting electron system when confined in a two-dimensional planar region. Such a confined set of electrons at low temperatures and with high magnetic fields exhibits a very unusual set of characteritics, which are of interest to theorists who wish to test and extend the basic thoery of electrons in crystalline solids. An improved theory then can be applied with more confidence to the wide range of metals and semiconductors which are of importance in microelectronics and other technologies. The experiments in this project are focusing on a "metal-insulator" transiton which ahs been observed and in particular on how it appears in connection with disorder in the environment of the electrons. On the one hand the experiments will provide new basic information about electrons when they are in interaction in confined layers at low temperatures. On the other hand the device structures which are used in these experiments are similar to those used in advanced microelectronic devices in the Gas technology. This research will involve students who will be well trained in the area of physics and will also gain familarity w ith semiconductor device technology, nd who will be excellently trained for employment in industry, government, or education. ***