Strained Ultrathin Interfaces for Controlled Molecular Self-Assembly

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***** NON-TECHNICAL ABSTRACT *****Self-assembly of ordered structures, a few nanometers wide, has been observed on many interfaces critical to novel nano-technologies. The formation of these structures is thought to arise because of a delicate balance between long-range strain field interactions and short-range chemical forces that stabilize the structures. A detailed understanding of the driving forces, however, does not exist. The goal of this project is to identify and control these interactions, which have the potential to radically improve the performance of electronic, magnetic, and chemical devices and sensors; and may lead the way to higher density magnetic storage, more selective catalytic materials, higher sensitivity chemical sensors, and perhaps, quantum computers. The integrated experimental/computational research approach combines time-resolved atomic microscopy in ultrahigh vacuum and elastic modeling of the dynamics of self-assembly at the atomic scale in conjunction with appropriate electronic structure calculations. The graduate and undergraduate students involved in this research will receive training in skills that will enable them to become productive members of the future scientific workforce. This research will form an integral part of an educational outreach program through contributions to a hands-on course, Physics for High School Teachers, and a Summer Nano-Science Institute for local high school students and their teachers, in order to address the need to improve the science achievement for students by enriching science teaching in the high school classroom. This award receives support from the Condensed Matter Physics and the Electronic and Photonic Materials programs.***** TECHNICAL ABSTRACT *****This award funds studies to characterize, control, and understand the atomic processes in self-organized growth that lead to two-dimensional pattern formation in strained ultrathin interfaces, such as single graphene and metal layers on crystalline substrates. The integrated experimental/computational approach combines time-resolved atomic measurements by scanning tunneling microscopy (STM) and low-energy electron microscopy (LEEM) and elastic modeling of the dynamics of self-assembly at the atomic scale in conjunction with appropriate first-principles and tight-binding electronic structure calculations. A novel analysis method of LEEM data will deliver the compositional (sub-)surface profile in these heterogeneous systems, crucial input for modeling and linking to theory. The graduate and undergraduate students involved in this research will receive training in skills that will enable them to become productive members of the future scientific workforce. The projects form an integral part of educational outreach programs. Through contributions to a hands-on course, Physics for High School Teachers, and a Summer Nano-Science Institute for local high school students and their science teachers the project addresses the need to improve the science achievement for students by enriching science teaching in the high school classroom. These activities are directed toward improving the recruitment into Science, Engineering, Technology, and Mathematics (STEM) careers by making significant contributions to science education at the pre-college level. This award receives support from the Condensed Matter Physics and the Electronic and Photonic Materials programs.