Fabrication and Physics of Electron Systems in AlAs Quantum Wells

点击翻译按钮获取中文摘要

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.