Fabrication and Physics of Electron Systems in AlAs Quantum Wells

本课程将研究高品质量子限制半导体结构中的电子交互作用物理。 该计划包括两个制造的研究，通过分子束外延技术，并在低温和高磁场的电子相关现象占主导地位的电子输运性质。 工作的重点是新的，高品质的二维电子系统（2DES）局限于选择性掺杂的AlAs量子威尔斯，这些2DES的参数是非常不同的标准2DES在GaAs。 几个问题，包括谷简并对整数和分数量子霍尔态的影响，以及自旋自由度对量子霍尔态之间跃迁的作用将被研究。该项目将由研究生和本科生进行，他们将在晶体生长，制造和电气测量的关键领域接受培训。首席研究员和他的团队将参加普林斯顿大学的K-12教师教育项目，并在自由科学中心进行演示。固态物理学中最吸引人的领域之一是关于物质的新状态，这些新状态主要是由于电子之间的相互作用而产生的。为了探索这种状态，需要将包括杂质和晶体缺陷在内的缺陷减少到最低限度的样品。本研究涉及此类样品的制造，以及对其新颖电子特性的测量。重点是砷化铝量子威尔斯中的二维电子系统。这些样品的参数与通常研究的砷化镓样品非常不同。对新样品中观察到的状态和现象的理解不仅将推进我们对基础物理的知识，而且还可以导致新的器件概念。这项研究的一个主要组成部分是在晶体生长，半导体样品处理和电气测量的关键领域的研究生和本科生的培训和教育。在这一领域训练有素的学生将是美国以及世界其他地区的宝贵资源。 首席研究员和他的团队将参加普林斯顿大学的K-12教师教育项目，并在自由科学中心进行演示。

An investigation of electron interaction physics in high-quality, quantum-confined semiconductor structures will be conducted. The program includes studies of both fabrication, via the molecular beam epitaxy technique, and of electronic transport properties at low temperatures and high magnetic fields where electron correlation phenomena dominate. The emphasis of the work is on novel, high-quality two-dimensional electron systems (2DESs) confined to selectively-doped AlAs quantum wells; these 2DESs have parameters that are very different from those of the standard 2DESs in GaAs. Several problems, including the influence of valley degeneracy on the integer and fractional quantum Hall states, and the role of the spin degree of freedom on transitions between the quantum Hall states will be studied. The project will be carried out by graduate and undergraduate students who will be trained in crucial areas of crystal growth, fabrication, and electrical measurements. The principal investigator and his group will take part in the K-12 teacher education programs at Princeton University and also present demonstrations at the Liberty Science Center. One of the most fascinating areas in solid state physics concerns new states of matter that come about primarily because of the interaction between the electrons. To explore such states, one needs specimens in which the imperfections, including impurities and crystal defects, are reduced to a minimum. This study involves the fabrication of such samples, and measurements of their novel electronic properties. The emphasis is on two-dimensional electron systems in aluminum-arsenide quantum wells. These have parameters that are very different from the commonly studied gallium-arsenide samples. An understanding of the states and phenomena observed in the new samples not only will advance our knowledge of fundamental physics, but can also lead to novel device concepts. A major component of this research is the training and education of graduate and undergraduate students in critical areas of crystal growth, semiconductor sample processing, and electrical measurements. Well-trained students in this field will be invaluable resources for the US as well as the rest of the world. The principal investigator and his group will take part in the K-12 teacher education programs at Princeton University and also present demonstrations at the Liberty Science Center.