FIP Seminar: Tracking the dynamics of atoms in materials with scattering experiments and computer simulations

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Wed, 11/20/2019 - 12:00 to 13:00

Presenter

Dr. Olivier Delaire, Associate Professor of Mechanical Engineering and Materials Science, Associate Professor of Chemistry, Duke University

A detailed view of atomic motions in crystals is needed to refine microscopic theories of energy transport and thermodynamics, and to design next-generation materials. Understanding the behavior of atomic vibrations (phonons) is key to rationalize numerous functional properties, ranging from ferroelectrics for sonar, to superionics for safer solid batteries, to thermoelectrics for waste-heat harvesting, or metal-insulator transitions for ultrafast transistors. Near phase transitions, one needs to properly account for deviations from the phonon gas model of textbooks, by including effects of phonon-phonon or electron-phonon couplings. These interactions could open the door to further tuning of materials properties for improved functionality.

This presentation will overview our methods and investigations of atomic dynamics in several classes of materials ranging from ferroelectrics to thermoelectrics or solid-state electrolytes. We will highlight the thermodynamics and ultrafast mechanism of the fascinating metal-insulator phase transition in vanadium dioxide (VO2), which were studied with a combination of neutron scattering, ultrafast pump-probe measurements, and first-principles simulations. The presentation will conclude with some possible scientific opportunities.

Olivier Delaire obtained a PhD in Materials Science from Caltech (2006). After a postdoc at Caltech, he became a Clifford Shull fellow at Oak Ridge National Lab (2008), and subsequently a Staff Researcher at ORNL (2012-2015). Since 2016, he is Associate Professor at Duke University. His group leads projects investigating atomic dynamics in a wide range of materials for energy applications, sensing, and information storage.