MEMS Seminar: Olivier Delaire, ““The Dynamics of Atoms in Solids – from Early Breakthroughs to Current Challenges”

Thomas Lord Department of Mechanical Engineering & Materials Science invites Dr. Olivier Delaire (Duke) to present the MEMS Seminar, “The Dynamics of Atoms in Solids – from Early Breakthroughs to Current Challenges.”
ABSTRACT: From Einstein’s and Debye’s models for the heat capacity , through Peierls’ early theory of thermal conductivity , and the Bardeen-Cooper-Schrieffer theory of superconductivity , the importance of atomic motions in solids has been established early on as a central aspect of materials science. Solids are not static and the motions of ions within them (either vibrational or diffusive, and sometimes more unusual) underlie many thermodynamic and transport properties. Probing and rationalizing these atomic dynamics is important from both a fundamental standpoint and to enable the design and engineering of desired material properties. Yet, the complex dynamics and couplings between degrees-of-freedom underpinning numerous material properties remain insufficiently understood.
This talk will survey our research and how we provided new insights into atomic dynamics in materials. By combining scattering experiments with large-scale atomistic modeling and machine learning, we probe the atomic structure and dynamics in solids, from fast ionic diffusion in solid-state electrolytes to phonon transport and thermal conductivity in thermoelectrics, or electron-phonon coupling and structural transitions in metal-halide perovskites for photovoltaics and optoelectronics. Our experiments map spatio-temporal correlations, revealing details of atomic structure and dynamics in materials, their disorder and correlations. In parallel, our atomistic simulations help rationalize experimental results, for example with DFT, ab-initio molecular dynamics and machine-learning accelerated simulations. The presentation will highlight some of the results from the Delaire lab over the past decade.

OLIVIER DELAIRE obtained his PhD in Materials Science from Caltech (2006). He joined Oak Ridge National Laboratory as a Clifford Shull Fellow in the Neutron Sciences Directorate (2008), later becoming Staff Researcher in the Materials Science and Technology Division (2012). In 2016, he became Associate Professor in the Thomas Lord Department of Mechanical Engineering and Materials Science at Duke University, with secondary appointments in the Physics and Chemistry departments.