Chapter 17 - Molecular beam epitaxy of complex oxides

Abstract

Complex oxides are in the focus of research in materials science and condensed matter physics because of their wide spectrum of material properties and their intriguing phenomena arising from competing interaction with spin, charge, lattice and orbital degrees of freedom. It is stemming from the seemingly endless possibilities to combine two or more elements with oxygen to a stable compound with differences in the cation type, oxygen coordination, bonding geometry and thus crystal structure. Advancing the knowledge by establishing a structure-property relationship at the atomic scale and harnessing the functionality in these materials in next generation devices and application requires the synthesis of high quality complex oxide thin films. Common thin film growth techniques have their specific sets of challenges being a main reason why the utilization and integration of complex oxide materials into electronic devices is still in its infancy. In this chapter the growth of complex oxides with perovskite and related structures and the specific challenges associated with the thin film growth of these compounds by molecular beam epitaxy are reviewed. A hybrid growth approach is discussed that combines the advantages of molecular beam epitaxy and chemical beam epitaxy in an ideal way. The growth of SrTiO 3 employing this growth technique is reviewed in detail. Stoichiometric SrTiO 3 films can be reproducibly grown by entering a self-regulated growth window accessible in hybrid MBE for complex titanates. The success of this new growth method is discussed by highlighting the material quality improvements and future research opportunities to explore the exciting physics in complex oxides are given.