Edge States in Two-Dimensional Electron Gas Systems at High Magnetic Fields Studies in Terms Spectroscopic Approach.

1.边沿态的色散关系：与非平衡边沿态分布相关联的输运特性表明，当T低于0.1K时，边沿态由可压缩区域和不可压缩区域组成，但当B=3T时，随着T的增加，边状态的色散趋于平缓。边态和体态：考虑到多余的边电荷的一致计算得出了化学势引起的边缘电流与静电势引起的霍尔电流之间的比率。同时，由于所有电子对外加微扰的响应而产生的“响应电流”与由费米面上的电子几率振幅电流引起的“费米面电流”是不同的。这两种电流是传输电流的另一种定义，它们分别导致量子化霍尔效应(QHE)的体像和边缘像。(1)发展了远红外(FIR)范围内的超高灵敏度探测器，以实现目标研究。利用QHE器件，获得了比传统的Ge光导探测器高出三个数量级以上的灵敏度。(2)用上述探测器探测了QHE区无耗散二维电子气的回旋发射。对3000多个小霍尔棒阵列的研究表明，发射存在一个阈值霍尔电压：EV_H=Homega_c/2。结果表明，发射与来自触点的电子注入有关，有助于更好地理解触点与二维电子气系统之间的电子交换机制。QHE击穿的非局域性：对霍尔棒中纵向电场空间演化的研究表明，自举类型的电子加热导致了QHE击穿。

1. Dispersion relation of edge states : Transport characteristics associated with non-equilibrium edge state distribution indicated that the edge states consist of compressible and incompressible regions at low T below 0.1K but the dispersion smoothes with increasing T up to 0.5K at B=3T.2. Edge states and bulk states : A consistent calculation taking the excess edge charges into account derived the ratio between the edge current due to chemical potential and the Hall current due to electrostatic potential. Also, the "response current" due to all the electrons responding to the imposed perturbation was distinguished from the "Fermi-surface current" due to the current of the probability amplitude of the electrons on the Fermi surface. These two are alternative definitions of transport current, which lead to the bulk picture and the edge picture of the quantized Hall effedts (QHE), respectively.Mechanism and location of energy dissipation in the Quantum Hall effects (QHE)(1) Ultra-high sensitive detectors in the far-infrared (FIR) range were developed to make the aimed studies possible. By using QHE devices, a sensitivity by more than three orders of magnitude higher than that of the conventional Ge photoconductive detectors was achieved.(2) The cyclotron emission from dissipation-less two-demensional electron gas (2DEG) in the QHE regime was detected by the detectors above. Studies on an array of more than 3000 small Hall bars revealed that there is a threshold Hall voltage for the emission ; eV_H=homega_c/2. The results show that the emission is associated with the injection of electrons from contacts, and contributed to better understanding of the mechanism of exchange of electrons between contacts and the 2DEG system.4. Nonlocal nature of the breakdown of the QHE : Studies of spatial evolution of longitudinal electric field in Hall bars indicated that the bootstrap-type electron heating causes the QHE to breakdown.