Electronic Properties of Two Dimensional Electron Systems: Exploring the Role of Dimensionality Boundaries and Interfaces.

*技术摘要*二维电子系统由于其空间维度的降低和不完全屏蔽，呈现出三维电子系统所不具备的奇异的电子性质和新颖的关联相。到目前为止，尽管通过研究捕获在半导体界面上的常规二维电子系统取得了重要的进展和发现，但许多问题仍然悬而未决。这里提出的工作将使用石墨烯，这是二维电子系统家族的最新成员之一，以解决由于低温和高磁场下电荷载流子的降维、屏蔽、边界和手性而产生的新的电子性质和相关电子相的问题。回答这些问题可能是新型应用的关键，包括超高速电子学和量子计算机的构建块。实验探针将包括低温强磁场扫描隧道显微镜、扫描隧道光谱、朗道能级光谱和磁输运。拟议的研究将为年轻研究人员提供最先进的纳米制造和光谱技术的良好培训基础。此外，这项研究项目提供的信息具有直接性和直观性，便于向学生和公众传达物理学和纳米科学的兴奋。*非技术抽象*我们周围的一切，从最小的生物到最大的物体都是三维的。我们对世界的看法和理解，以及支配世界的物理定律，都植根于这三个空间维度：长度、宽度和高度。如果这些维度中的一个被拿走，把我们留在谚语中的“平地”，会发生什么？事实证明，奇怪和违反直觉的现象可能会发生，因为在这样一个二维世界中，描述原子和电子微观世界行为的理论在宏观长度尺度上变得明显。该项目将继续进行实验，在最近发现的二维系统石墨烯中探索这些新类型的量子现象。石墨烯是由只有一个原子厚度的结晶碳制成的薄膜，是迄今为止已知的真正的二维系统中最接近的实现。该项目将使用最先进的实验科学工具：纳米制造、低温、高磁场、原子分辨率扫描隧道显微镜和光谱分析，以探测和操纵石墨烯的性质。可能的结果包括创造出具有可以通过施加磁场或栅极电压来调节特性的新型电子相，以及有朝一日可能成为量子计算机构建块的器件。该项目将支持对年轻研究人员进行最先进的科学和技术应用方面的教育，为从学术界到最先进的技术行业等广泛的科学职业提供一个极好的培训场所。

****TECHNICAL ABSTRACT****Two dimensional electron systems, by virtue of their reduced spatial dimension and incomplete screening, present exotic electronic properties and novel correlated phases which are unavailable in three dimensional counterparts. To date, in spite of important advances and discoveries made by studying the conventional two dimensional electron systems trapped at semiconductor interfaces, many questions remain open. The work proposed here will employ graphene, one of the latest additions to the family of two dimensional electron systems, to address questions regarding novel electronic properties and correlated electron phases that arise due to the reduced dimensionality, screening, boundaries and chiral nature of the charge carriers at low temperatures and in high magnetic fields. Answering these questions may hold the key to novel application including ultra-fast electronics and building blocks for quantum computers. The experimental probes will include low temperature high-magnetic field scanning tunneling microscopy, scanning tunneling spectroscopy, Landau level spectroscopy and magneto-transport. The proposed research will provide an excellent training ground for young researchers in state of the art nano-fabrication and spectroscopy techniques. In addition, the direct and visually oriented nature of the information from this research project will make it easy to communicate the excitement of physics and nano-science to students and to the general public. ****NON-TECHNICAL ABSTRACT****Everything around us, from the smallest creature to the largest object is three dimensional. Our views and understanding of the world as well as the laws of physics governing it are grounded in this trio of spatial dimensions: length, width and height. What would happen if one of these dimensions were taken away leaving us in a proverbial "flatland". It turns out that strange and counterintuitive phenomena can occur because in such a two-dimensional world quantum mechanics, the theory which describes the behavior of the microscopic world of atoms and electrons, becomes manifest at macroscopic length scales. This project will pursue experiments to probe these new types of quantum phenomena in a recently discovered two-dimensional system, graphene. Graphene a membrane made of crystalline Carbon which is only one atom thick is the closest realization of a truly two dimensional system known to date. The project will employ the most advanced tools of experimental science: nanofabrication, low temperatures, high magnetic fields, atomic resolution scanning tunneling microscopy and spectroscopy, to probe and manipulate the properties of graphene. Possible outcomes include the creation of novel electronic phases with properties that can be tuned by applying a magnetic field or a gate voltage, and devices that could one day serve as building blocks for quantum computers. This project will support the education of young researchers in state of the art science and technological applications providing an excellent training ground for a broad spectrum of scientific careers ranging from academia to the most advanced technology industries.