Plenary Session 3 (8:30 ~ 9:50, Nov. 14, 2023)

Chair: Professor Naoki Ohashi (National Institute for Materials Science, Japan) 

Plenary Talk - 5

Thermodynamics and Phase-field Method of Ferroelectric Polar Structures

Long-Qing Chen

Department of Materials Science and Engineering and Materials Research Institute, Penn State University, University Park, PA 16802, USA

Phase-field method has been established as a powerful mesoscale computational approach that can be used to interpret and understand experimentally observed microstructures. This presentation will discuss the thermodynamic basis of the phase-field method and its applications to understanding and predicting the ferroelectric domain structures and their evolution under both static and dynamic external stimuli. The focus will be on a few examples on our recent efforts to employ the phase-field method to not only interpret and understand experimentally observed ferroelectric polar domain patterns but also provide guidance to experimental synthesis and characterization to discover new mesoscale ferroelectric domain states or achieve dramatically enhanced properties. Examples include the simulation-guided observation of polar vortex lattices and skyrmions in ferroelectric heterostructures, understanding of the roles of light-excited electronic carriers in the topological phase transformations of polar structures under static electric field or under light, synthesis of ferroelectric relaxor ceramics and single crystals for record-high piezoelectricity, and the discovery of simultaneous near-perfect light transparency and ultrahigh piezoelectricity through control poling protocols. The presentation will end with a perspective on the future applications of the phase-field method to understanding and predicting the mesoscale polar structures and their interactions with electronic and lattice defects as well as their electromechanical and optical responses.

About the speaker

Professor Chen is Donald W. Hamer Professor of Materials Science and Engineering. He received his Ph.D. from MIT, M.S. from Stony Brook University, and B.S. from Zhejiang University. He joined the faculty at Penn State in 1992. His main research interests include thermodynamics and kinetics of phase transformations and computational microstructure model development. His research awards include Material Research Society Materials Theory Award, Guggenheim Fellowship, Humboldt Research Award, TMS John Bardeen Award, Fellow of TMS, MRS, AAAS, APS, ASM, and ACerS, and Member of Academia of Europaea (MAE, Academy of Europe).