title: Lattice and strain analysis of atomic resolution Z-contrast images based on template matching.
abstract: A real space approach is developed based on template matching for quantitative lattice analysis using atomic resolution Z-contrast images. The method, called TeMA, uses the template of an atomic column, or a group of atomic columns, to transform the image into a lattice of correlation peaks. This is helped by using a local intensity adjusted correlation and by the design of templates. Lattice analysis is performed on the correlation peaks. A reference lattice is used to correct for scan noise and scan distortions in the recorded images. Using these methods, we demonstrate that a precision of few picometers is achievable in lattice measurement using aberration corrected Z-contrast images. For application, we apply the methods to strain analysis of a molecular beam epitaxy (MBE) grown LaMnO₃ and SrMnO₃ superlattice. The results show alternating epitaxial strain inside the superlattice and its variations across interfaces at the spatial resolution of a single perovskite unit cell. Our methods are general, model free and provide high spatial resolution for lattice analysis.
authors.affiliation: Department of Materials Science and Engineering, University of Illinois, Urbana, IL 61801, USA; Seitz Materials Research Laboratory, University of Illinois, Urbana, IL 61801, USA. Electronic address: jianzuo@uiuc.edu.
authors.forename: Jian-Min
authors.initials: JM
authors.lastname: Zuo
authors.forename: Amish B
authors.initials: AB
authors.lastname: Shah
authors.forename: Honggyu
authors.initials: H
authors.lastname: Kim
authors.forename: Yifei
authors.initials: Y
authors.lastname: Meng
authors.forename: Wenpei
authors.initials: W
authors.lastname: Gao
authors.forename: Jean-Luc
authors.initials: JL
authors.lastname: Rouviére
keywords: STEM; Strain analysis; Template matching; Z-contrast