Quantum Transport in Non-Equilibrium Two-Dimensional Electron Systems

*非技术摘要*该奖项支持对半导体量子器件中远离平衡系统的电子行为的实验研究，最近在该系统中发现了令人惊讶的新效应。例如，如在现有的NSF支持下发现的那样，半导体器件中的电输运在暴露于微波时可以表现出消失电阻。这项研究项目将研究微波与小磁场相结合对这些器件中电子传输的影响。此外，还将使用一种对磁场敏感的独特显微镜，对微波感应零阻状态下的电子流模式进行成像。了解由微波驱动的半导体器件的基本性质直接关系到未来技术中出现的问题，如“自旋电子学”(利用器件中电子的磁性和电性)和“量子信息处理”(利用量子力学行为存储和处理信息)。这项研究将由研究生进行，本科生也将参与。研究生将学习半导体物理、微波技术和成像技术，这将为他们在国家研究基础设施和高科技产业中的就业提供良好的服务。*技术摘要*由最先进的GaAs/AlGaAs技术提供的高迁移率二维电子系统(2DES)是一个干净的多电子物理实验室。这一个人研究人员奖支持一种新的2D物理制度的实验研究；2DES中的量子输运受到远离平衡条件的影响。主题包括新发现的辐射诱导电阻振荡现象和毫米波照射下2DES的零阻/零电导状态，直流电流诱导磁阻振荡和非线性输运，毫米波区域的非线性光学效应及其对直流电子输运的影响。该项目将扩展到标准的直流传输，包括使用低温扫描霍尔探针显微镜对微波诱导的零阻状态下的电流流动模式进行成像实验。它将探索在微波驱动的电子系统中半经典和量子区域的电子流图样的形成。这些研究将由研究生进行，本科生也将参与。研究生将学习半导体物理、微波技术和成像技术，这将为他们在国家研究基础设施和高科技行业就业提供良好的服务。

****NON-TECHNICAL ABSTRACT****This award supports experimental investigation of electronic behavior in a far-from-equilibrium system in a semiconductor quantum device, where surprising new effects have been recently discovered. For example, as discovered under prior NSF support, electrical transport in a semiconductor device can exhibit vanishing resistance when it is exposed to microwaves. This research project will investigate the effects of microwaves combined with small magnetic fields on the electronic transport in these devices. Additional experiments will image the electron flow pattern in the microwave-induced zero-resistance states using a unique microscope sensitive to magnetic fields. Understanding of fundamental properties of a semiconductor device driven by microwaves is directly relevant to emerging issues in future technologies such as "spintronics" (using the magnetic as well as electrical properties of electrons in devices) and "quantum information processing" (using quantum mechanical behavior to store and process information). The research will be carried out by graduate students and will also include the participation of undergraduate students. The graduate students will learn semiconductor physics, microwave technology, and imaging techniques, which will serve them well for employment in the national research infrastructure and high-technology industry.****TECHNICAL ABSTRACT****The high-mobility two-dimensional electron system (2DES) provided by the state-of-the-art GaAs/AlGaAs technology is a clean laboratory for many-electron physics. This individual investigator award supports experimental investigations of a new regime of 2D physics; the quantum transport in 2DES that is subjected to far-from-equilibrium conditions. The subject matter includes the newly discovered phenomenon of radiation-induced resistance oscillations and the zero-resistance/zero-conductance states in a 2DES exposed to millimeter wavelength electromagnetic waves, dc current-induced magnetoresistance oscillations and nonlinear transport, and nonlinear optical effects in the millimeter wave regime and their influence to dc electronic transport. The project will expand beyond the standard dc transport, to include imaging experiments on the current flow pattern in microwave-induced zero-resistance states using a low temperature scanning Hall probe microscope. It will explore the electron flow pattern formation in the semi-classical and quantum regimes in a microwave-driven electronic system. The studies will be carried out by graduate students and will also include the participation of undergraduate students. The graduate students will learn semiconductor physics, microwave technology, and imaging techniques, which will serve them well for employment in the national research infrastructure and high-technology industry.