Investigation of Anti-dot Superlattice in Quantum Hall State

我们研究了不同类型二维电子系统中的量子现象，得到了以下结果：在相对均匀的样品中，量子霍尔效应的击穿电流与样品宽度不成正比，而在非均匀样品和具有反点超晶格的样品中，击穿电流与宽度成正比。我们解释这些结果是由于不均匀电位或反点引起的均匀霍尔电场。证实了分数阶量子霍尔区边缘态的存在，并通过磁电容测量确定了边缘态的宽度。估计宽度为微米数量级，这与整数量子霍尔体系中的宽度相似。我们观察到二维电子系统中的费米面由于磁场平行而产生的磁电子聚焦效应所引起的畸变。畸变的电子浓度依赖性取决于改变电子浓度的方法（通过照明或栅极电压）。利用远红外傅里叶磁谱仪测量了双层二维电子系统的回旋共振，其中磁场方向是可变的。系统地确定了费米曲面畸变引起的回旋加速器质量对平行磁场的依赖关系。

We have investigated the quantum phenomena in various type of two-dimensional electron system and obtained the following results.1. The breakdown current of quantum Hall effect is not proportional to the sample width in relatively homogeneous samples, while the current is proportional to the width in inhomogeneous samples and the sample with anti-dot superlattice.We explain these results due to the uniform Hall electric field caused by the inhomogeneous potential or anti-dots.2. The existence of the edge state in the fractional quantum Hall regime is confirmed and its width is determined by the magneto-capacitance measurement.The estimated width is of the order of microns, which is similar to the width in the integer quantum Hall regime.3. We observe the distortion of Fermi surface in the two-dimensional electron system due to the parallel magnetic fields by the magnetic electron focusing effect.The electron concentration dependence of the distortion depends on the methods to change the concentration (by illumination or the gate voltage).4. The cyclotron resonance of the double-layer two-dimensional electron system is measured is investigated by the Far-infrared Fourier magneto-spectrometer, where the magnetic field direction is changeable.The parallel magnetic field dependence of the cyclotron mass due to the distortion of Fermi surface is determined systematically.