CAREER: Nanoscopy Of Surface States In Two-Dimensional Materials

摘要：技术的快速进步往往是由新材料和物理现象的发现所驱动的。二维层状材料在现代材料研究中表现出一些最引人注目的物理现象，并有望在未来广泛的设备和技术应用中发挥作用，从柔性电子到能量收集和存储再到生物工程。本项目探讨了由于纳米尺度上的协同多体相互作用而产生的层状二维晶体上的涌现电子和激子表面态。这些研究将促进我们对控制下一代纳米光电器件的电子和光学特性的表面状态的基本理解，以及二维纳米激光器的可行性。这些研究活动是综合教育计划的一部分，旨在促进大亚特兰大地区高中生、本科生和研究生的纳米科学和纳米光学学习。该研究还与加强当地高中物理教师和学生的教育和培训的外展活动以及针对亚特兰大地区非洲移民学生/家庭和非洲裔美国青年的教育经验的社区外展计划相结合。技术摘要：CAREER奖的研究部分利用最先进的远场和纳米近场光谱技术探索了范德华层状二维晶体的电子和激子表面态。本研究的目标是：(i)了解二维系统中表面态，金属和导电表面态以及拓扑保护表面态的基本性质；（ii）了解岛边和缺陷处激子（带电和中性）的性质，阐明激子二维材料与表面等离子体之间的耦合机制，特别是原子薄材料垂直堆叠制备的激子范德华异质结构的受激发射机制；（iii）扩大光学、红外和太赫兹散射扫描近场光学显微镜方法在低维物理领域的范围和应用。所提出的研究结果将促进我们对控制二维新兴材料系统的电子和光学性质的表面态的基本理解，并将导致奇异的多体物理学和自旋电子学，实用量子计算机和固态量子光子学的应用。

Nontechnical Abstract: Rapid technological advances are often driven by the discovery of new materials and physical phenomena. Two-dimensional layered materials exhibit some of the most striking physical phenomena in modern materials research and hold promise for a wide range of future devices and technological applications from flexible electronics to energy harvesting and storage to bio-engineering. This project explores emergent electronic and excitonic surface states on layered two-dimensional crystals that arise due to the concerted many-body interactions at nanometer length scales. These investigations will advance our fundamental understanding of surface states that govern the electronic and optical properties of the next-generation nano-optoelectronic devices and the feasibility of two-dimensional nanolasers. These research activities are part of an integrated education plan to further high school, undergraduate and graduate students' nanoscience and nano-optics learning in the greater Atlanta area. The research is also integrated with outreach activities to enhance the education and training of local high school physics teachers and students as well as with community outreach plans that targets the educational experience of African immigrant students/families and African American youth in the Atlanta area.Technical Abstract: The research part of this CAREER award explores the electronic and excitonic surface states on van der Waals layered two-dimensional crystals using state-of-the-art far-field and nanoscale near-field spectroscopy. The goals of this research are: (i) understand the fundamental properties of surface states in two-dimensional systems, metallic and conducting surfaces states and topologically protected surface states; (ii) understand the properties of excitons (charged and neutral) at island edges and defects and elucidate the coupling mechanism between excitonic two-dimensional materials and surface plasmons, in particular the mechanism of stimulated emission in excitonic van der Waals heterostructures made by vertically stacking atomic thin materials; and (iii) expand the scope and utility of optical, infrared and terahertz scattering scanning near-field optical microscopy approaches in the field of low-dimensional physics. The results of the proposed research will forward our underlying understanding of surface states that control the electronic and optical properties of two-dimensional emergent material systems and will lead to exotic many-body physics and applications in spintronics, practical quantum computers and solid-state quantum photonics.