CAREER: Dielectric Screening - From First Principles to Mesoscale

University Of Illinois At Urbana-Champaign, Urbana IL

Investigators

Abstract

NONTECHNICAL SUMMARY This CAREER award supports research and education in designing and discovering novel optical materials using computer simulations. The quantum mechanical nature of atoms and electrons governs the behavior of materials at microscopic length- and time scales, but at large scales a fully atomistic approach is intractable. Computer simulations that bridge different length scales carry the promise of bringing fundamental research closer to manufacturing: New materials and technological applications could be developed faster and cheaper. That is particularly true for optical materials that are, for instance, needed for photovoltaic devices and energy production, displays, and novel efficient sensors for biological and medical applications. In this project, the research team seeks to develop an approach for computational design and discovery of optical materials across multiple length scales. The researchers will improve approximations that are used to achieve a quantum mechanical description of optical absorption. This in turn will enable the team to successfully describe materials with strong interactions between electrons and ions, a subject of intense current interest. Based on the results of these predictive simulations, the team will abandon the atomistic resolution of the model in order to simulate optical materials that are structured at nanoscale dimensions. The team will incorporate data from recently developed public online databases into the computational framework aiming to discover new candidate materials and investigate their suitability for modern optical applications. The input and output research data sets will be made publicly available for advanced verification and validation, and possibly unforeseen uses, e.g. in data-mining. While the broader availability of supercomputers transforms how modern research is done, skilled, interdisciplinary researchers are becoming an essential component. For that reason, the research project is tightly integrated with educational activities to train the next-generation workforce at the nexus of materials and computer science. The PI will incorporate computer simulations into the undergraduate curriculum at the University of Illinois at Urbana-Champaign, and develop computational learning modules that can be directly used in the classroom. The PI will also build an interdisciplinary team of undergraduate researchers to develop virtual-reality-based techniques for education and exciting outreach to a large audience, which includes high school and undergraduate students. This will be achieved by new techniques for interactive visualization of simulation results in three dimensions using a smartphone. All codes and implementations developed for research, the computational modules for education, and the virtual-reality apps for education and outreach in high schools will be documented and made accessible to the broader research and education community. TECHNICAL SUMMARY This CAREER award supports research and education in the development of a computational materials science framework with predictive power across multiple length scales. The framework will enable the research team to accurately describe optical properties and allow for computer-aided design and discovery of novel optical materials. The researchers will extend presently used first-principles quantum-mechanical techniques to overcome limitations that lead to large uncertainties for optical absorption spectra, and especially for excitonic effects in polar materials. They will achieve multiscale predictions for nanostructured materials by solving Maxwell equations, and they will develop approaches to screen online data repositories for excited-state properties. This framework will allow the design and discovery of novel optical materials, entirely based on computer simulations. To achieve the goals of this project, the research team will develop detailed understanding of complicated electron-electron and electron-ion interactions based on parameter-free quantum-mechanical simulations. They will improve the description of dielectric screening by accounting for contributions from free carriers and the lattice, overcoming uncertainties for novel polar materials. Using these results in Maxwell-equation-based modeling of nanostructured materials eliminates the dependence on input from experiment, and extends the atomistic first-principles simulations into the nanoscale regime. The team will use existing data from large density-functional theory based online databases to learn about excited-state properties, and to facilitate the discovery of new optical materials within tens of thousands of available datasets. This project will develop generally applicable techniques and use them to understand polar materials with desirable characteristics, e.g. for plasmonic applications. While the broader availability of supercomputers transforms how modern research is done, skilled, interdisciplinary researchers are becoming an essential component. For that reason, the research project is tightly integrated with educational activities to train the next-generation workforce at the nexus of materials and computer science. The PI will incorporate computer simulations into the undergraduate curriculum at the University of Illinois at Urbana-Champaign, and develop computational learning modules that can be directly used in the classroom. The PI will also build an interdisciplinary team of undergraduate researchers to develop virtual-reality-based techniques for education and exciting outreach to a large audience, which includes high school and undergraduate students. This will be achieved by new techniques for interactive visualization of simulation results in three dimensions using a smartphone. All codes and implementations developed for research, the computational modules for education, and the virtual-reality apps for education and outreach in high schools will be documented and made accessible to the broader research and education community.