Study of Quantum Hall Liquids using Single Electron Transistors

******非技术摘要******在高磁场下，被限制在两个方向上运动的电子形成了被称为分数量子霍尔液体的物质的新状态。在这种物质中，新粒子的出现具有非常不寻常的性质。例如，在大多数导体中，电流通常由带e电荷的电子携带。在超导体中，电流由带2e电荷的电子对携带。相比之下，在分数量子霍尔液体中，电流由分数电荷为e/3、e/5等的不寻常粒子携带。由于已知电子是不可分割的，所以这种部分带电粒子的出现一直是许多电子量子现象中最迷人的表现之一。这个项目将使用一种叫做单电子晶体管的设备来研究这些迷人的新粒子。单电子晶体管可以通过一个电子打开和关闭，因此是目前最灵敏的电荷传感器。使用这种类型的高灵敏度晶体管，量子霍尔液体的磁性也将被探索。在教育方面，该项目将为参与的研究生和本科生提供半导体物理和纳米科学方面的优秀培训。此外，还将与当地科学博物馆合作开展外展活动，以提高K-12学生对科学和工程的兴趣。******技术摘要******本项目将解决二维电子系统中一些长期存在的基本问题。分数量子霍尔液体的激发被预测为携带分数电荷，并遵循不同于费米子或玻色子的不寻常的分数统计。准粒子的分数化和统计将在反点几何结构中使用单电子晶体管进行研究，这将允许研究人员进行噪声和Aharonov-Bohm型干涉实验。载流子的统计将首先通过在反点周围加载可控制电荷量的边缘状态，然后通过在干涉实验中监测相位变化来解决。使用单电子晶体管来研究量子霍尔液体的体输运特性，将使研究深入到传统输运测量无法进行的绝缘状态。在教育方面，该项目将为参与的研究生和本科生提供半导体物理和纳米科学方面的优秀培训。此外，还将与当地科学博物馆合作开展外展活动，以提高K-12学生对科学和工程的兴趣。

******NON-TECHNICAL ABSTRACT******At high magnetic fields, electrons that are confined to move in two directions form new states of matter known as fractional quantum Hall liquids. In such matter, new particles emerge with very unusual properties. For example, in most conductors electrical current is normally carried by electrons with a well-known charge of e. In superconductors, current is carried by pairs of electrons with a charge of 2e. By contrast, in fractional quantum Hall liquids, current is carried by unusual particles with fractional charge of e/3, e/5, and so on. Since electrons are known to be indivisible, the emergence of such fractionally charged particles has been one most fascinating manifestations of many electron quantum phenomena. This project will study these fascinating new particles using devices called single electron transistors. The single electron transistor can be turned on and off by a single electron, and is thus the most sensitive charge sensor in existence. Using this type of a highly sensitive transistor, magnetic properties of quantum Hall liquids will also be explored. On the educational side, the project will provide excellent training for participating graduate and undergraduate students in semiconductor physics and nanoscience. In addition, an outreach activity will be mounted in collaboration with a local science museum to promote the interest of K-12 students in science and engineering. ******TECHNICAL ABSTRACT******This project will address some long-standing fundamental problems in two-dimensional electron systems. Excitations of fractional quantum Hall liquids are predicted to carry fractional charge and obey unusual fractional statistics different from those of fermions or bosons. Fractionalization and statistics of quasiparticles will be studied using single electron transistors in an antidot geometry, which will allow the researchers to perform both noise and Aharonov-Bohm type interference experiments. The statistics of the carriers will be addressed by first loading the edge states around the antidot with a controllable amount of charge and then by monitoring the phase change in an interference experiment. The use of single electron transistors to study bulk transport properties in quantum Hall liquids will enable investigations deep in the insulating regime where conventional transport measurements cannot be performed. On the educational side, the project will provide excellent training for participating graduate and undergraduate students in semiconductor physics and nanoscience. In addition, an outreach activity will be mounted in collaboration with a local science museum to promote the interest of K-12 students in science and engineering.