Invited
Epitaxial Thin-Film, Multilayer, and Superlattice Ferroelectrics – From Growth to Understanding

Over the last 30 years, the study of ferroelectric oxides has been revolutionized by the implementation of epitaxial-thin-film-based studies, which have driven many advances in the understanding of ferroelectric physics and the realization of novel polar structures and functionalities. New questions have motivated the development of advanced synthesis, characterization, and simulations of epitaxial thin films and, in turn, have provided new insights and applications across the micro-, meso-, and macroscopic length scales. This tutorial will trace the evolution of ferroelectric thin-film research through the early days developing understanding of the roles of size and strain on ferroelectrics to the present day, where such understanding is used to create complex hierarchical domain structures, novel polar topologies, and controlled chemical and defect profiles. We will delve into some of the major approaches being used today to produce epitaxial thin films, including techniques like pulsed-laser deposition, sputtering, molecular-beam epitaxy, and more. Such approaches enable not only the production of new materials, but also the development of new understanding and control of ferroelectric functionalities beyond what we once thought possible. Finally, we will explore how researchers are actively working to apply lessons from these fields in a number of applications, including novel memory and logic architectures, as well as a host of energy-conversion devices.