CAREER: Structure and Electronic Anomalies of Vitreous Matter

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The electronic structure of a material, including electronic energies and wavefunctions, determines its electronic and optical properties. In turn, these properties underlie a myriad of important implications for energy conversion, transportation and storage, renewable energy production, information processing and storage, catalysis, optical devices, and many others. Even if the atomic locations in a material are known, inspection of the electronic structure is difficult because of the need to simultaneously solve for the dynamics of many electrons that are strongly interacting. Amorphous materials, such as window glasses, pose a still greater challenge to the chemist due to the difficulty to determine their structure via techniques that have worked well for periodic crystals, such as X-ray diffraction. Amorphous materials, in particular those made by rapid cooling of a liquid melt, are important in applications due to their low manufacturing costs and numerous unique properties not found in periodic crystals. For example, alloys containing elements from groups 5 and 6, such as antimony and tellurium, are presently used to make optical drives and are the leading candidate for next generation computer memory. Another important example is viscous ionic liquids, which are used to make batteries. The project aims to trace the origin of the unique optoelectronic anomalies of vitreous (i.e., glassy) solids to the atomic motions above the glass transition which, surprisingly, occurs subject to very strict statistical rules. The project focuses on the dynamics of a viscous liquid above the glass transition which is to be mapped onto seemingly different model systems that are defined on a fixed lattice. By connecting the parameters of these models with the properties of specific substances, a microscopic description of glassy solids is expected whereby structure and electronic properties emerge self-consistently. Solutions to the important problem of the electronic structure of amorphous materials lies at the interface of chemistry, physics, and materials science. These factors combine to create a unique multidisciplinary research environment for participating students and researchers, and for communicating to high school students the fascinating properties of viscous liquids and amorphous materials. Considering the ethnic diversity at the University of Houston and in the greater Houston area, the research enhances the educational opportunities of underrepresented groups and promotes their participation in advanced research. Local writers and radio personalities are collaborating to publicize the societal benefits of the research resulting from this project. In addition to the fundamental significance of the research on vitreous materials, other potential benefits include new ways to manufacture efficient computer memory, solar cells, batteries, optical fibers, and many others.