New Findings in Materials in Extreme Environments
| Date/Time: | Friday, 09 Nov 2018 from 3:10 pm to 4:00 pm |
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| Location: | Phys 0003 |
| Phone: | 515-294-5441 |
| Channel: | College of Liberal Arts and Sciences |
| Actions: | Download iCal/vCal | Email Reminder |
Abstract: Extreme pressures and temperatures produce profound effects on structure, bonding and electronic character of atoms and molecules, molding matter to make new materials. A growing number of novel materials and phenomena are being documented over the broad range of conditions using both static and dynamic multimegabar (e.g., >300 GPa) pressures that can now be generated in the laboratory. The results are leading to altogether new structures, electronic phenomena and potentially useful materials, with implications for condensed matter physics, geophysics, planetary physics, astrophysics, and at more modest conditions even biophysics. Because of its quantum character and putatively simple electronic structure, the behavior of hydrogen has been of particular interest. Recent studies of hydrogen have uncovered new transformations to increasingly metallic states in both the solid and fluid using static and dynamic compression methods to multimegabar pressures. There have also been important recent findings in hydrogen-rich systems in a variety of chemical environments at these conditions. Most notable is our discovery of a new class of materials - superhydrides - and the observation of near room-temperature superconductivity in one of these systems, lanthanum superhydride, at pressures close to 200 GPa.
Bio: Professor Russell Hemley explores the nature of materials in extreme environments, specifically high pressures, and temperatures. The work includes high-pressure experimental and theoretical studies in chemistry and physics, earth and planetary science, soft matter and biology, and the creation of new materials for technology using extreme conditions. After three decades at the Geophysical Laboratory and the Carnegie Institution of Washington, he moved to George Washington University where he is a research professor in the Department of Civil and Environmental Engineering. He is the director of the DOE/Carnegie Alliance Center (CDAC), a Center of Excellence funded by DOE/NNSA; the director of Energy Frontier Research in Extreme Environments (EFree), a DOE Energy Frontier Research Center, co-executive director of the A. P. Sloan Foundation-funded Deep Carbon Observatory; and chair of the JASON Advisory Group. He is a Fellow of the American Academy of Arts and Sciences, Member of the National Academy of Sciences, Corresponding Fellow of the Royal Society of Edinburgh, and Honoris Causa Professor of the Russian Academy of Sciences. Dr. Hemley received his Ph.D. from Harvard University in 1983, his M.A. from Harvard University in 1980 and his B.A. from Wesleyan University in 1977.