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(公共法律111-5)资助的。*非技术摘要*局限于半导体界面的二维电子气一直是当代凝聚态物理的重要模型系统之一。当主体半导体中的无序程度足够低，温度的随机化效应降低时，电子就可以在丰富的各种有趣的相中自由有序。历史上，随着样品质量的不断提高，新的电子相不断被发现。一些阶段已经很好地理解了，而另一些阶段目前正在紧张的调查中。与利用电子在系统中的直流传输进行更常见的研究不同，该项目将使用热力学测量来探索已知电子相以前无法获得的性质，并深入了解新发现的奇异相的性质。这些实验将使用最先进的低温和电子仪器以及现代半导体工艺。除了促进我们对这些耐人寻味的系统的基本理解外，这项研究还可能对未来的技术产生影响。该项目将教育一名博士生现代凝聚态物理和培训先进技术。事实证明，在这一领域的工作是为从学术界到工业界的广泛科学事业做好准备的极好准备。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大部分知识来自于对二维电子气的研究。当受到低温和外加磁场的作用时，这些系统会显示出大量的奇异电子相。一些位相，如整数和分数量子霍尔态，以及Wigner固体，都是很好理解的。其他州，如具有偶数分母填充因素的州，正在接受严密的调查。这个项目将利用热力学测量来探索和阐明受限关联电子的不寻常性质。将使用一种新的技术，即在稀释冰箱温度下将系统中的电子与声子去耦合。这些测量将为已知但尚未完全理解的阶段提供新的见解，并提供关于最新发现的状态的信息。该项目将通过学习现代凝聚态物理和培训现代半导体工艺、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职业生涯提供极好的准备。本科生将被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.