Magnetotransport and Millimeter Wave Spectroscopy of a Partially Filled Landau Level

本实验研究项目是研究分数量子霍尔效应下二维电子气体的磁输运和毫米波波谱，特别是部分填充朗道能级下复合费米子的性质。该实验为探索量子霍尔系统动力学打开了一扇新的窗口。内部结构，即束缚态的色散w(q)，以及束缚态的固有波动，将被研究。能量在1-10K之间可调谐的毫米波将通过表面金属光栅或周期性密度调制耦合到二维气体中，并且将使用灵敏的微分光导技术进行检测。实验还将涉及纳米结构技术，如高分辨率电子束光刻和加工。这个实验研究项目致力于研究一个被限制在二维平面区域内的导电电子系统的基本性质。这样一组被限制在低温和高磁场下的电子显示出一组非常不寻常的特征，在某些方面，相关的实体不是电子在真空中的行为，而是具有可分离自旋和电荷特性的“准粒子”。这种情况下的“复合费米子”将被研究，方法是将无线电波照射到它们身上，并测量它们对无线电波的反应。一方面，这些实验将提供关于电子在低温条件下在受限层中相互作用的新的基本信息。另一方面，这些实验中使用的器件结构与GaAs技术中使用的先进微电子器件相似。这项研究将涉及在物理领域受过良好训练的学生，他们将熟悉半导体器件技术，并将为工业，政府或教育部门的就业提供出色的培训。＊＊＊

9705521 Du This experimental research project is a study of magnetotransport and millimeter wave spectroscopy of the 2-D electron gas in the fractional quantum Hall effect regime, specifically the properties of composite Fermions in a partially filled Landau level. The experiments open a new window to probe dynamics of the quantum Hall system. The internal structure, ie, the dispersion w(q) of the bound states, and the inherent fluctuations of the bound states, will be investigated. Millimeter waves tunable in energy from 1-10K will couple into the 2-D gas via a surface metal grating or periodic density modulation, and a sensitive differential photoconductivity technique will be used for detection. The experiments will also involve nanostructure techniques such as high-resolution electron-beam lithography and processing. %%% This experimental research project is devoted to basic properties of a conducting electron system when confined into 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 characteristics, and in some ways the entities which are relevant are not electrons behaving as they behave in vacuum, but "quasi-particles" having separable spin and charge properties. The "composite Fermions" of this situation are to be studied by shining radio waves onto them and making measurments to determine the response to the radio waves. 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 GaAs technology. This research will involve students who will be well trained in the area of physics and will also gain familiarity with semiconductor device technolgy, and who will be excellently trained for employment in industry, government, or education. ***