CWRU Physics Faculty

Gary S. Chottiner
Professor of Physics
B.S., Carnegie Mellon University (1974)
M.S., University of Maryland (1976)
Ph.D., University of Maryland (1980)
Condensed Matter Experiment; Surface Science and Thin Films
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Many of the properties associated with solids (and liquids) are determined more by the surface layers of those materials than by their bulk composition. An investigation of surface properties requires that attention be paid to both fundamental and practical issues. An example of the former is that the law of conservation of momentum is different for the two dimensional world of surfaces than it is in "normal" three dimensional space. Practical concerns include the segregation of bulk impurities to a surface, the adsorption of contaminants which requires working in ultrahigh vacuum (about 10-13 atmospheres), rearrangements of surface atoms compared to their equivalent bulk positions, and related changes in bonding between atoms and electronic behavior.

Explanations developed over the past century for the bulk behavior of materials often break down when attempts are made to apply them to surfaces. Condensed matter theorists are just beginning to tackle these issues with confidence. However, a broad range of experimental techniques are available to measure the geometrical, chemical, and electronic structures of a sample's top one to three atomic layers. In the Physics Department's Surface Science/Thin Film Laboratories, we employ X-ray Photoelectron Spectroscopy, Auger Electron Spectroscopy, Low Energy Electron Diffraction, Temperature Programmed Desorption Spectroscopy, Scanning Tunneling/Atomic Force Microscopy, Fourier Transform Infrared Spectroscopy, and various other tools to examine surface and thin film phenomena.

Much of our work is done in collaboration with scientists and engineers from other disciplines. This is common in the fields of surface and thin film science because the issues being addressed frequently have broad technological implications. For example, chemical reactions such as oxidation, the catalytic production of gasoline, and the catalytic reduction of pollutants in automobile exhaust depend on surface properties. Bonding in modern composites and the performance of optical coatings, adhesives, and sealants rely on reactions between surface layers. The behavior of the small electronic components used in large scale integrated devices depends on the thin films and on the material interfaces inherent in such devices. Many of the systems that have been studied recently in our research group are of interest because of their relevance to energy use and storage. These include the reactions of lithium with certain molecules that may be used in rechargeable lithium batteries (making electric cars more economical), the behavior of small clusters of Pt atoms (which can differ from bulk Pt and from individual atoms and could lead to new and more efficient catalysts and fuel cells), and the surface properties of high temperature materials such as sapphire, silicon carbide, and diamond that may someday appear in more efficient engines and may even replace silicon as the basis for computing technology.