CAREER: Broadband Microwave and THz Investigations of Correlated Electron and Nanostructure Systems

职业：相关电子和纳米结构系统的宽带微波和太赫兹研究

• 批准号: 0847652
• 负责人: Norman Armitage
• 金额: $ 52.5万
• 依托单位: Johns Hopkins University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-03-01 至 2014-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0847652&HistoricalAwards=false
• 关键词: CAREER; Broadband; Microwave; THz; Investigations

TECHNICAL ABSTRACTThe response of condensed matter to electromagnetic radiation is a fundamental probe of its electronic structure. Correlated systems and their nanostructures like quantum magnets, high-Tc superconductors, 2D electron gasses, graphene and others exhibit a multitude of novel properties as a result of strong electron-electron interactions, reduced dimensionality, and interfacial effects. Unfortunately, many of their natural time scales lie in the GHz and THz region of the electromagnetic spectrum that has been difficult to access in a broadband manner. The upper part of this range has even become known as the `Terahertz Gap', which is a range of frequencies (roughly 0.05 to 10 THz) and energy scales above what is easily accessible with radio-frequency and microwave electronics, but below that accessible easily with conventional optics. Recently, however, there have been a series of dramatic breakthroughs in broadband microwave GHz range and time-domain THz spectroscopy that allow measurements which were simply not possible previously. This proposal for research at The Johns Hopkins University is aimed at the exploitation of these recent dramatic advances in GHz and THz range spectroscopic techniques for the investigation of exotic electronic states of matter at low temperatures. The systems to be investigated include novel dielectrics, electronic glasses, nanostructures such as interfacial metal heterostructures and graphene, and materials in proximity to quantum (T=0) phase transitions. These systems are of central importance for intellectual issues at the forefront of condensed matter physics and their exploration in the GHz and THz spectral range offers great scientific opportunity. The proposed work is of particular educational value to students owing to the material science and low frequency electrodynamics techniques that will be employed and which are finding broad application in research and private industry. In this regards, specific teaching laboratories will be developed. Public outreach activities in the form of the Johns Hopkins Physics Fair will also be realized.NON-TECHNICAL ABSTRACT: It is hardly an exaggeration that most of what we know about physical systems comes from their response to perturbations at their characteristic frequencies. For instance, the fundamental tone of a plucked violin string depends on the length of the string, the tension in it, and its thickness. This is true from the acoustics of a violin to the energies of atoms. Unfortunately the natural frequency scales of many solid materials fall in a range which has been prohibitively difficult to access technically until recently. This project takes advantage of recent dramatic technical advances in THz and microwave spectroscopy to characterize the natural frequency scales of solids. Material systems like superconductors, which can conduct electricity without resistance and various magnetic states will be studied. The investigations performed herein will give absolutely essential information to develop new materials with important technological implications. These technological developments are coupled to a broad initiative in education and outreach. The proposed work is of particular educational value to students owing to the material science and low frequency electrodynamics techniques that will be employed and which are finding broad application in research and private industry. Specific teaching laboratories will be developed. Public outreach activities in the form of the Johns Hopkins Physics Fair will also be realized.

技术摘要凝结物对电磁辐射的响应是其电子结构的基本探测。 相关系统及其纳米结构，例如量子磁铁，高-TC超导体，2D电子气体，石墨烯等，由于强烈的电子电子相互作用，尺寸降低和界面效应，因此具有多种新型特性。 不幸的是，它们的许多自然时间尺度位于电磁频谱的GHz和THZ区域，这很难以宽带方式进入。该范围的上部甚至被称为“ Terahertz Gap”，它是一系列频率（大约0.05至10 THz），并且能量尺度以上是可轻松访问的射频和微波电子设备，但是在下面可以轻松访问常规光学器件。然而，最近，在宽带微波GHz范围和时间域THZ光谱法中，已经进行了一系列戏剧性的突破，这些范围允许以前根本无法进行测量。约翰·霍普金斯大学（Johns Hopkins University）的这项研究提案旨在剥削GHz和THZ范围光谱技术最近的这些急剧进步，以调查低温下物质的外来电子状态。要研究的系统包括新型电介质，电子玻璃，纳米结构，例如界面金属异质结构和石墨烯，以及与量子（t = 0）相变的材料。这些系统对于在凝结物理学的最前沿的智力问题及其在GHz和THZ光谱范围的探索方面至关重要。 由于材料科学和低频电动动力学技术，这些工作对学生具有特别的教育价值，这些技术将被采用，并且在研究和私营企业中发现了广泛的应用。 在这方面，将开发特定的教学实验室。 以约翰·霍普金斯物理博览会的形式进行公共宣传活动也将被实现。没有技术摘要：我们对物理系统所知道的大多数人对它们的特征频率的反应并不是夸张的。 例如，拔出小提琴弦的基本音调取决于弦的长度，其中的张力和其厚度。 从小提琴的声学到原子的能量，这是正确的。 不幸的是，许多固体材料的固有频率尺度属于该范围，直到最近才能在技术上很难获得。该项目利用了最近在THZ和微波光谱方面的巨大技术进步来表征固体的固有频率尺度。将研究可以在没有阻力和各种磁性状态的无电力的超导体等材料系统中进行研究。 本文进行的调查将提供绝对重要的信息，以开发具有重要技术意义的新材料。 这些技术发展与教育和宣传方面的广泛倡议相结合。由于材料科学和低频电动动力学技术，这些工作对学生具有特别的教育价值，这些技术将被采用，并且在研究和私营企业中发现了广泛的应用。将开发特定的教学实验室。也将实现以约翰·霍普金斯物理博览会形式的公共外展活动。