Aharonov-Bohm Excitons in Stacked Type-II Quantum Dots: Physics, Storage, and Manipulation

摘要：本项目将研究半导体纳米结构中的Aharonov-Bohm效应，其中载流子位于不同的位置。Aharonov-Bohm效应是量子力学中最引人入胜的反直觉现象之一：带电粒子即使在磁场之外也能“感觉到”磁场。这种效应在经典物理学中无法解释。当空间分离的载流子重组时发出的光可以被储存——“冻结在原地”，然后通过外部磁场和电场的适当组合按需释放。这种行为为操纵固体中的光开辟了一条可靠的途径，对信息技术、计算和国家安全具有深远的影响。这项研究将采用先进的科学工具，如纳米制造、强磁场、强大的激光和复杂的计算来完成。将利用国家实验室现有的先进设备。该项目将支持博士研究生的教育，他们将接触到一系列相互关联的成长、特征和理论分析问题，这些问题历来是教育、学术界和工业界许多科学事业的优秀培训。此外，该项目将让本科生参与暑期研究，并通过与社区学校合作吸引高中生。技术摘要：本项目将研究堆叠ii型量子点中的激子。这些所谓的ii型激子是由空间分离的电子和空穴产生的；这样的一对整体为零电荷，具有电偶极子，在磁通量存在的情况下产生在光学发射中可观察到的Aharonov-Bohm相。要利用的技术包括磁发光（连续波和时间分辨）在可变温度下有或没有外电场。利用适当的磁场和电场组合，可以控制和操纵Aharonov-Bohm激子的寿命。电场的作用是消除轨道动量简并，并根据需要在亮态和暗态之间切换激子。该项目的最终目标是能够将光存储在Aharonov-Bohm激子中，然后可以在受控时间重新发射光子。这些实验有望引起科学界的普遍兴趣，并为操纵固体中的光和通过基于激子的集成电路进行量子计算提供可靠的途径。该项目将支持一名博士生的教育，该博士生将接触到一系列相互关联的生长、特征和理论分析问题，这些问题长期以来一直是教育、学术界和工业界许多科学事业的优秀培训。此外，该项目还将通过与社区学校的合作，让本科生和高中生参与暑期研究。

NON-TECHNICAL ABSTRACT: This project will investigate the so-called Aharonov-Bohm effect in semiconductor nanostructures, where charge carriers reside in different locations. The Aharonov-Bohm effect is one of the most fascinating and counter-intuitive phenomena in quantum mechanics: a charged particle can "feel" a magnetic field even when it remains outside this field. This effect does not have an explanation in classical physics. The light emitted when spatially separated charge carriers recombine can be stored - "frozen in place", then released on demand via a proper combination of external magnetic and electric fields. This behavior opens a credible route for the manipulation of light in solids with profound implications for information technology, computation, and national security. This research will be accomplished by employing such advanced scientific tools as nanofabrication, high magnetic fields, powerful lasers, and sophisticated computation. Advanced facilities available at National Laboratories will be utilized. This project will support the education of a PhD student, who will be exposed to an array of interrelated issues of growth, characterization, and theoretical analysis, which historically has been excellent training for many scientific careers in education, academia, and industry. In addition, the project will involve undergraduate students in summer research as well as attract high-school students through cooperation with neighborhood schools.TECHNICAL ABSTRACT: This project will investigate excitons in stacked type-II quantum dots. These, so-called type-II, excitons are created by a spatially separated electron and hole; such a pair, having overall zero charge, possesses an electric dipole, which in the presence of the magnetic flux give rise to the Aharonov-Bohm phase, observable in optical emission. The techniques to be utilized include magneto-luminescence (continuous wave and time-resolved) at variable temperatures with and without an external electric field. Using the proper combination of the magnetic and electric fields, the lifetime of the Aharonov-Bohm excitons will be controlled and manipulated. The role of the electric field is to remove the orbital momentum degeneracy, and switch the exciton between its bright and dark states on demand. The ultimate goal of this project is to be able to store the light in the Aharonov-Bohm exciton, which then can re-emit a photon at a controlled time. These experiments are expected to be of general interest to the scientific community as well as to provide a credible route for the manipulation of light in solids and for quantum computation via exciton-based integrated circuits. This project will support the education of a PhD student who will be exposed to an array of interrelated issues of growth, characterization, and theoretical analysis, which, for a long time, has been excellent training for many scientific careers in education, academia, and industry. In addition, the project will involve undergraduate students in summer research as well as high-school students, through cooperation with neighborhood schools.