Research Progress on Ferroelectric Superlattices

Ferroelectric superlattices are artificial film materials with layered periodic structure formed by an alternate growth of two or more ferroelectric materials or non-ferroelectric materials at unit cell scale.Ferroelectric superlattices can exhibit excellent ferroelectric, piezoelectric, dielectric, and pyroelectric properties due to the existence of a large number of heterogeneous interfaces and the remarkable interface effect, and even show new functional properties that are not available in their constituent materials.Therefore, ferroelectric superlattices not only provide an ideal platform for studying interactions between charges and lattices at the interface of complex oxide materials, but also play an indispensable role in the next generation of integrated ferroelectric devices.With the development of preparation and characterization methods, researchers can design and control the microstructure and 第 6 期 林俊良, 等: 铁电超晶格的研究进展 607 chemical composition at atomic scale to improve the functional properties of ferroelectric superlattice thin films.Ferroelectric polarization is the most basic property of ferroelectric film materials.In addition to being used for information storage devices, ferroelectric polarization also plays an important role in regulating the energy conversion performance of integrated ferroelectric devices such as piezoelectric devices, photovoltaic devices and electrocaloric devices.Therefore, the ferroelectric polarization intensity of ferroelectric superlattices directly determines their functional characteristics and practical application value of integrated ferroelectric devices composed of them.In this short review paper, we firstly introduced the structural characteristics, classification and several typical functional characteristics of ferroelectric superlattices, and then focused on several factors affecting the polarization performance of ferroelectric superlattices based on recent research results, including strain effect, electrostatic coupling effect, defect effect, and period thickness.Finally, we looked forward to the future research directions in ferroelectric superlattices to provide reference for the research in this field.