Oxide Molecular Beam Epitaxy of Highly-Perfect Thin Film Perovskites

University Of California-Santa Barbara, Santa Barbara CA

Investigators

Abstract

NON-TECHNICAL DESCRIPTION The project focuses on oxide materials that exhibit unique functionalities not found in any other materials class, such as ferroelectricity, superconductivity or electric field tunable dielectric constants. These properties are of great interest for potential application in new devices for communication, computing or digital memories. A major objective of the project is the development of techniques to obtain thin films of these oxide materials with unprecedented perfection. Highly-perfect materials are needed, not only for improved properties, but also to gain fundamental insights into the physics of these materials. The understanding gained in this project will be used towards the development of atomic-scale engineered film structures that make use of the unique properties of oxide materials. The project will contribute to the interdisciplinary training of graduate and undergraduate students through collaboration with theorists and training in both formal (courses and weekly seminars) and informal (shared laboratory) settings. The project will provide opportunities for internships for undergraduate students and teachers. TECHNICAL DETAILS The goal of the proposed project is the development of highly perfect, epitaxial complex oxide thin films and heterostructures by molecular beam epitaxy (MBE). The project builds on novel oxide MBE approaches that overcome known challenges, such as oxygen deficiency, and that allow for the growth of stoichiometric films with high purity and low defect concentrations. The project focuses on technologically important perovskites, such as SrTiO3 and BaTiO3 and their solid solutions, which exhibit unique functionalities, such as ferroelectricity, superconductivity or tunable dielectric constants. The dielectric and electrical properties of insulating and conducting films are documented and, in conjunction with growth studies and physical measurements, used to establish the role of interfaces and defects in the properties of oxide films and heterostructures. The research is timely, because not only have high defect concentrations limited widespread application of these materials, but also because highly perfect films are needed for a fundamental understanding of the unique phenomena observed in oxide heterostructures. The project contributes to the interdisciplinary training of graduate and undergraduate students in advanced thin film growth and characterization of novel materials through collaborations and training in both formal (courses and seminars) and informal settings. The project provides opportunities for internships for undergraduate students and physical science teachers.