Low-Energy Charge Dynamics in Dirac Fermion Materials

狄拉克费米子材料中的低能电荷动力学

• 批准号: 1007020
• 负责人: Ward Beyermann
• 金额: $ 34.5万
• 依托单位: University of California-Riverside
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-08-15 至 2014-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1007020&HistoricalAwards=false
• 关键词: Low; Energy; Charge; Dynamics; Dirac

Technical Abstract:The objective of this project is to better understand the exotic change dynamics in materials with a Dirac point close to the Fermi energy in their band structure. The classic example is graphene; however, topological insulators, which are bulk insulators, also have Dirac fermions in unique metallic chiral edge states. Despite numerous theoretical and experimental papers on this topic, several issues are still unresolved regarding the low-frequency conductivity, the importance of quasiparticle interactions and the role of impurities and defects in their electronic properties. Terahertz time-domain spectroscopy will be used to investigate the response of these materials in this previously unexplored frequency range. Along with important fundamental issues, these materials have the potential for new technological functionality from high-performance electronic devices to topological quantum computing. Understanding the charge dynamics at terahertz frequencies is a crucial component for pursuing some of these applications. Finally, this project will train two graduate students and postdoc in a quickly emerging area of nanoscience. UCR runs a Summer Bridge to Research program that supports summer research for undergraduates in STEM fields who are Hispanic and/or come from low-income families. Each summer, a student in this program will participate on this project.Non-Technical Abstract:As a result of their unique structure, Dirac fermion materials, such as graphene and topological insulators, have exotic electronic properties and display a wide range of fascinating phenomena, which is the reason they have attracted an enormous amount of interest. Fundamentally related to their properties is the response of the electrons to external electric fields. The objective of this project is to investigate this response at terahertz frequencies using time-domain spectroscopy. This type of an investigation in a previously unexplored frequency range is relevant to resolving several issues related to how the electrons interact with defects and with each other. These materials have the potential for new technological functionality from high-performance electronic devices to topological quantum computing. In addition to advancing our fundamental understanding, knowledge of the electron?s response at these frequencies is important for pursuing some of these new applications. Finally, this project will train two graduate students and postdoc in a quickly emerging area of nanoscience. UCR runs a Summer Bridge to Research program that supports summer research for undergraduates in STEM fields who are Hispanic and/or come from low-income families. Each summer, a student in this program will participate on this project.

技术摘要：本项目的目的是更好地理解带结构中狄拉克点接近费米能量的材料的奇异变化动力学。典型的例子是石墨烯；然而，拓扑绝缘体，即体绝缘体，也具有独特的金属手性边缘态的狄拉克费米子。尽管有许多关于这一主题的理论和实验论文，但关于低频电导率，准粒子相互作用的重要性以及杂质和缺陷在其电子特性中的作用等几个问题仍未得到解决。太赫兹时域光谱学将用于研究这些材料在这个以前未探索的频率范围内的响应。除了重要的基础问题外，这些材料还具有从高性能电子设备到拓扑量子计算的新技术功能的潜力。了解太赫兹频率下的电荷动态是实现这些应用的关键组成部分。最后，该项目将在纳米科学这一新兴领域培养两名研究生和博士后。加州大学洛杉矶分校（UCR）开展了一个“夏季研究之桥”项目，为STEM领域的西班牙裔和/或来自低收入家庭的本科生提供夏季研究支持。每年夏天，这个项目的一名学生将参与这个项目。摘要：狄拉克费米子材料，如石墨烯和拓扑绝缘体，由于其独特的结构，具有奇异的电子特性，并显示出广泛的迷人现象，这是它们吸引了大量兴趣的原因。与它们的性质基本相关的是电子对外部电场的响应。该项目的目的是利用时域光谱学研究太赫兹频率下的这种响应。在以前未探索的频率范围内进行的这种类型的调查与解决与电子如何与缺陷相互作用以及彼此相互作用有关的几个问题有关。这些材料具有从高性能电子设备到拓扑量子计算的新技术功能的潜力。除了提高我们对电子的基本认识之外？在这些频率上的S响应对于追求这些新的应用是很重要的。最后，该项目将在纳米科学这一新兴领域培养两名研究生和博士后。加州大学洛杉矶分校（UCR）开展了一个“夏季研究之桥”项目，为STEM领域的西班牙裔和/或来自低收入家庭的本科生提供夏季研究支持。每年夏天，这个项目的一名学生将参与这个项目。