Determining Structural Prototypes of Ferroelectrics - Theory and Applications in Perovskite Materials

Learn about structural prototypes of ferroelectrics in this comprehensive lecture from Michele Kotiuga of École Polytechnique Fédérale de Lausanne. Explore a symmetry-based methodology for identifying meaningful structural prototypes for local disorder in paraelectric and ferroelectric phases, with a focus on using these prototypes as minimal structural models for calculations. Discover how to construct prototypes through group-subgroup analysis refined with density-functional-theory calculations, using barium titanate as a case study. Examine how the methodology systematically explores and identifies structural prototypes for the paraelectric phase while maintaining cubic point symmetry. Follow the extension of these findings across perovskite titanates, niobates, and zirconates, as well as their application to lower-symmetry ferroelectric phases. Delve into topics including complex displacements, size zone boundaries, potential energy landscapes, mixed composition phases, and the behavior of these materials under pressure.