Thermodynamic Measurements of Collective Phases of Two-Dimensionally Confined Charge Carriers

该奖项是根据2009年美国复苏和再投资法案（公法111-5）资助的。限制在半导体界面上的二维电子气是当代凝聚态物理的重要模型体系之一。当主体半导体中的无序水平足够低并且温度的随机化效应降低时，电子可以自由地在各种各样的有趣的相中有序化。历史上，随着样品质量的不断提高，新的电子相被发现。有些阶段已经很好理解，而另一些阶段目前正在进行深入调查。 而不是更常见的研究利用直流传输的电子通过系统，该项目将使用热力学测量探测以前无法访问的属性已知的电子阶段，并产生洞察的性质，新发现的，异国情调的阶段。实验将采用最先进的低温和电子仪器以及现代半导体加工技术。 除了推进我们对这些有趣系统的基本理解外，这项研究还可能对未来技术产生影响。 该项目将培养一名现代凝聚态物理学博士生，并进行先进技术培训。在这样一个领域的工作被证明是一个很好的准备，从学术界到工业界的科学事业的大范围。本科生将被介绍凝聚态物理的概念和技术。*技术摘要 * 我们对低维费米子系统的许多认识来自于对二维电子气的研究。当受到低温和外部磁场，这些系统表现出大量的外来电子相。一些相位，如整数和分数量子霍尔态和维格纳固体是很好的理解。 其他国家，如甚至分母填充因子正在紧张的调查。本计画将利用热力学量测来探索与阐明受限关联电子的不寻常性质。 将使用一种新的技术，它采用了在稀释冰箱温度下的系统中的电子从声子的去耦。这些测量将对已知但尚未完全理解的阶段产生新的见解，并提供有关最近发现的状态的信息。该项目将通过研究现代凝聚态物理学和现代半导体加工培训，进行低水平测量和使用低温设备，为研究生未来的学术或工业生涯提供良好的准备。本科生将介绍凝聚态物理的概念和技术。

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).***** NON- TECHNICAL ABSTRACT ****The two-dimensional electron gas confined to semiconductor interfaces has been one of the important model systems of contemporary condensed matter physics. When the level of disorder in the host semiconductor is low enough and the randomizing effect of temperature is reduced, the electrons are free to order in a rich variety of interesting phases. Historically, with the continuous improvement of sample quality new electronic phases have been discovered. Some phases are well understood while others are currently under intense investigation. Instead of the more common studies utilizing the dc transport of electrons through the system, this project will use thermodynamic measurements to probe previously inaccessible properties of known electronic phases and yield insight into the nature of the newly discovered, exotic phases. The experiments will employ state-of-the art cryogenic and electronic instruments and modern semiconductor processing. Aside from advancing our fundamental understanding of these intriguing systems, this research could have an impact of future technologies. This project will educate a doctoral student in modern condensed matter physics and training in advanced technologies. Work in such a field is proven to be an excellent preparation for a large spectrum of scientific careers from academia to industry. Undergraduate students will be introduced to concepts and techniques of condensed matter physics.****TECHNICAL ABSTRACT****Much of our knowledge of low dimensional fermionic systems comes from studies on two-dimensional electron gases. When subjected to low temperatures and an external magnetic field, these systems exhibit a large number of exotic electronic phases. Some of the phases such as the integer and fractional quantum Hall states and the Wigner solid are well understood. Others such as states with even denominator filling factors are under intense investigation. This project will utilize thermodynamic measurements to explore and elucidate the unusual properties of confined correlated electrons. A new technique will be used which employs the decoupling of the electrons from the phonons in the system at dilution refrigerator temperatures. These measurements will yield new insight into known but not fully understood phases as well as provide information on the most recently discovered states. This project will provide excellent preparation for graduate students for their future academic or industrial careers through the study of modern condensed matter physics and training in modern semiconductor processing, in conducting low level measurements, and in the use of cryogenic equipment. Undergraduate students will be introduced to concepts and techniques of condensed matter physics.