Presidential Young Investigator Award

二维电子基态的性质 系统（2DES）受到强磁场的影响， 吸引了大量的研究，无论是实验性的， 理论上的 由于系统地努力优化 设计和生长过程，他们已经开发了GaAs/GaAlAs 含有极高迁移率、低密度2DES的异质结构 无序度极低。 实现高质量 具有低电子浓度的2DES特别令人感兴趣 因为它们提供了实现和研究基础知识的手段， 2DES在一个新的极端磁量子体系中的性质 限制可用磁场。 磁传输，激活 传输和非线性传输测量将用于 研究2DES的集体态-分数量子 霍尔态和量子维格纳晶体-以及磁场- 在2DES中诱导定位。 辐射磁谱学 将用于研究这些状态下的集体激发。 电子束显微镜将用于制造 从相同的最先进的材料的纳米结构。 的 上述实验技术将被用来研究 限制几何中2DES的集体状态（低至200 A）。

The nature of the ground state of a two-dimensional electron system (2DES) subjected to an intense magnetic field has attracted a great deal of research, both experimental and theoretical. As a result of a systematic effort to optimize the design and the growth process they have developed GaAs/GaAlAs heterostructures containing very high-mobility, low-density 2DES with extremely low disorder. The realization of high-quality 2DES with low electron concentration is of particular interest because they provide the means to achieve and study fundamental properties of 2DES in a new regime of extreme magnetic quantum limit in available magnetic fields. Magnetotransport, activated transport and nonlinear transport measurements will be used to investigate collective states of 2DES - the Fractional Quantum Hall states and quantum Wigner crystal - and the magnetic-field- induced localization in 2DES. Radiofrequency magnetospectroscopy will be used to study collective excitations in these states. Electron beam microlitography will be used to fabricate nanostructures from the same state-of-the-art materials. The above described experimental techniques will be employed to study collective states of 2DES in restricted geometry (down to 200A).