Indirect Excitons in Semiconductor Nanostructures

*非技术摘要*这一个人研究人员奖支持对由非常薄的半导体层组成的结构的基本光学和电学性质的实验研究。这些纳米尺度的结构(即，它们具有十亿分之一米的微小长度尺度)被设计成允许创建被称为“间接激子”的新实体。现代信号处理设备，如计算机，是以电子控制为基础的，而光通信在信号传输中起着主要作用。由于实际电子设备既需要信号处理又需要传输，因此找到一种有效的光电系统，将电子操作和光通信统一起来，可能会给电子学带来革命性的变化。间接激子可以被电子控制并且可以产生光信号，因此这些实体对于未来的光电子器件可能是重要的。此外，间接激子是独一无二的，因为它们可以冷却到超低温度，在那里它们开始以量子力学的方式表现。这个项目旨在增加我们对超冷间接激子的基本物理的理解。特别是，它将解决预测的间接激子的量子力学行为。该项目的潜在影响是发展更多的凝聚态物理知识，更具体地说，是增加对材料中观察到的光学和电子现象的基本了解。这样的理解可能会带来开发先进光电子器件的令人兴奋的可能性。参与这个项目的学生将有机会对当代物理学的前沿进行探索性研究。*技术摘要*这个个人研究人员奖支持半导体纳米结构中冷激子气体的实验研究。激子是半导体中的电子-空穴束缚对。在低密度下，激子是类氢的、弱相互作用的玻色粒子。据预测，激子气体的量子简并温度较高，约为1K。由于间接激子的长寿命和高冷却速率，耦合量子阱中的间接激子形成了一个可以产生冷激子气体的系统。此外，间接激子可以通过光学和电子方式进行控制。该项目将探索在半导体纳米结构中实现和控制量子玻色气体的独特机会。特别是，该项目将研究量子激子气体中的新状态，包括理论预测的激子凝聚和最近观察到的新状态-宏观有序激子状态。这项研究有望加深我们对许多体系统中的光学相互作用和量子相干性的基本理解。拟议的研究将由学生进行，并将与教育相结合。

****NON-TECHNICAL ABSTRACT****This individual investigator award supports experimental studies of fundamental optical and electronic properties of structures made of very thin layers of semiconductors. These nanoscale structures (i.e, they have a tiny length scale of a billionth of a meter) are designed to allow the creation of new entities called "indirect excitons". Modern signal processing devices, such as computers, are based on electronic control while optical communication plays a major role in signal transmission. Since both signal processing and transmission are required for practical electronic devices, finding an effective optoelectronic system, which unifies electronic operations and optical communications, could revolutionize electronics. Indirect excitons can be electronically controlled and can produce optical signals, therefore these entities may be important for future optoelectronic devices. Furthermore, indirect excitons are unique because they can be cooled to ultralow temperatures where they start to behave in a quantum mechanical fashion. This project seeks to increase our understanding of the fundamental physics of ultracold indirect excitons. In particular it will address the predicted quantum mechanical behavior of the indirect excitons. The potential impact of the project is in development of increased knowledge in condensed matter physics, in general, and more specifically an increased fundamental understanding of the optical and electronic phenomena observed in materials. Such understanding may lead to the exciting possibility of developing advanced optoelectronic devices. The students involved with this project will have the opportunity to perform exploratory research on the cutting edge of contemporary physics. ****TECHNICAL ABSTRACT****This individual investigator award supports experimental studies of cold exciton gases in semiconductor nanostructures. An exciton is an electron-hole bound pair in a semiconductor. At low densities excitons are hydrogen-like, weakly interacting Bose particles. It has been predicted that the quantum degeneracy temperature of an exciton gas is relatively high, about 1K. Due to their long lifetime and high cooling rate, indirect excitons in coupled quantum wells form a system where a cold exciton gas can be created. Moreover, indirect excitons can be controlled optically and electronically. This project will explore the unique opportunities for implementation and control of quantum bosonic gases in semiconductor nanostructures. In particular, the project will investigate new states in quantum exciton gases, including theoretically predicted exciton condensates and a recently observed new state - the macroscopically ordered exciton state. This research is expected to increase our fundamental understanding of optical interactions and quantum coherence in many bodied systems. The proposed research will be performed by students and will be integrated with education.