title: Towards 3D Mapping of BO6 Octahedron Rotations at Perovskite Heterointerfaces, Unit Cell by Unit Cell.
abstract: The rich functionalities in the ABO3 perovskite oxides originate, at least in part, from the ability of the corner-connected BO6 octahedral network to host a large variety of cations through distortions and rotations. Characterizing these rotations, which have significant impact on both fundamental aspects of materials behavior and possible applications, remains a major challenge at heterointerfaces. In this work, we have developed a unique method to investigate BO6 rotation patterns in complex oxides ABO3 with unit cell resolution at heterointerfaces, where novel properties often emerge. Our method involves column shape analysis in ABF-STEM images of the ABO3 heterointerfaces taken in specific orientations. The rotating phase of BO6 octahedra can be identified for all three spatial dimensions without the need of case-by-case simulation. In several common rotation systems, quantitative measurements of all three rotation angles are now possible. Using this method, we examined interfaces between perovskites with distinct tilt systems as well as interfaces between tilted and untilted perovskites, identifying an unusual coupling behavior at the CaTiO3/LSAT interface. We believe this method will significantly improve our knowledge of complex oxide heterointerfaces.
authors.forename: Qian
authors.initials: Q
authors.lastname: He
authors.affiliation: Institute of Engineering Innovation, The University of Tokyo , 2-11-16, Yayoi, Bunkyo-ku, Tokyo 113-8656, Japan.
authors.forename: Ryo
authors.initials: R
authors.lastname: Ishikawa
authors.forename: Andrew R
authors.initials: AR
authors.lastname: Lupini
authors.forename: Liang
authors.initials: L
authors.lastname: Qiao
authors.affiliation: Department of Materials Science and Engineering, Drexel University , Philadelphia, Pennsylvania 19104, United States.
authors.forename: Eun J
authors.initials: EJ
authors.lastname: Moon
authors.affiliation: Department of Physics and Astronomy, Vanderbilt University , Nashville, Tennessee 37240, United States.
authors.forename: Oleg
authors.initials: O
authors.lastname: Ovchinnikov
authors.affiliation: Department of Materials Science and Engineering, Drexel University , Philadelphia, Pennsylvania 19104, United States.
authors.forename: Steven J
authors.initials: SJ
authors.lastname: May
authors.forename: Michael D
authors.initials: MD
authors.lastname: Biegalski
authors.forename: Albina Y
authors.initials: AY
authors.lastname: Borisevich
keywords: complex oxides; interfaces; octahedral rotations; scanning transmission electron microscopy