Experiments on the Role of Disorder in the Quantum Phases and Phase Transitions of Two-Dimensional Electrons

技术：半导体异质结中的二维电子系统(2DES)已经成为新物理现象的温床，表现出强关联物理，并为新的理论观点提供了试验场。过去对该系统的物理研究主要集中在理想清洁系统的关联物理上，实验是在当时可达到的最高迁移率的2DES上设计和进行的。这项研究将集中在三种新的材料/器件结构上，以获得以前无法获得的具有可控无序的稀疏2DES的物理区域。直流输运和微波光谱测量将在低温下进行，直到核退磁制冷机的温度范围，以寻找清洁的2DES中Wigner晶体和高度无序的2DES中Anderson绝缘体中间的电子物质的预期新相。它将教育学生凝聚态物理和半导体材料科学。他们将配备实验低温物理技术和半导体器件加工技术方面的实践专业知识。非技术：在现代电子学中，几乎所有的设备功能都是由电子执行的，这些电子被限制在薄膜中移动，或者沿着半导体的界面移动。半导体中的这种所谓的二维电子，尽管在正常环境下表现为普通的带电粒子气体，但在经过适当设计的实验条件下，它是新物理现象的温床，体现了强关联电子的量子物理学，也是新理论想法的试验场。这项研究将研究无序的影响，这在所有半导体中都是不可避免的，并探索一种新的物理制度，在这种制度下，无序和电子关联之间的相互作用有望产生电子物质的新相。这项研究是多学科的；它将教育学生流利地掌握凝聚态物理和半导体材料科学，并为他们配备实验低温物理技术和半导体器件加工技术的动手专业知识。

Technical:The two-dimensional electron systems (2DES) in semiconductor heterostructures has been a hot bed for new physical phenomena, manifesting strong correlation physics, and a testing ground for novel theoretical ideas. Physics research on the system has in the past mostly focused on the correlation physics of ideally clean systems and the experiments have been designed and carried out on 2DES with the highest mobility attainable at the time. This research will focus on three new material/device structures to access previously inaccessible physical regimes of dilute 2DES with controllably tunably disorder. DC transport and microwave spectroscopy measurements will be made at low T down to the nuclear demagnetization refrigerator temperature range to search for the expected new phases of electron matter intermediate to the Wigner crystal in clean 2DES and the Anderson insulator in highly disordered 2DES. It will educate students in condensed-matter physics and the science of semiconductor materials. They will be equipped with hands-on expertize in experimental low temperature physics techniques and semiconductor device processing technology. Non-Technical:In modern day electronics, almost all device functions are performed by electrons that are confined to move in thin films, or along the interfaces, of semiconductors. Such so-called two-dimensional electrons in semiconductors, though behaving at normal ambient as an ordinary gas of charged particles, have been under properly designed experimental conditions a hot bed for new physical phenomena, manifesting the quantum physics of strongly correlated electrons, and a testing ground for novel theoretical ideas. This research will investigate the influence of disorder, which is inevitable in all semiconductors, and explore a new physical regime, where the interplay between disorder and electron correlation is expected to give rise to new phases of the electron matter. The research is multidisciplinary in nature; it will educate students to be fluent in condensed-matter physics and the science of semiconductor materials, and equip them with hands-on expertize in experimental low temperature physics techniques and the processing technology of semiconductor devices.