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.
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.
