Atomic-scale structure relaxation, chemistry and charge distribution of dislocation cores in SrTiO3

Peng Gao; Ryo Ishikawa; Bin Feng; Akihito Kumamoto; Naoya Shibata; Yuichi Ikuhara

doi:10.1016/j.ultramic.2017.09.006

Atomic-scale structure relaxation, chemistry and charge distribution of dislocation cores in SrTiO₃

Ultramicroscopy. 2018 Jan;184(Pt A):217-224. doi: 10.1016/j.ultramic.2017.09.006. Epub 2017 Sep 23.

Authors

Peng Gao¹, Ryo Ishikawa², Bin Feng², Akihito Kumamoto², Naoya Shibata³, Yuichi Ikuhara⁴

Affiliations

¹ Institute of Engineering Innovation, School of Engineering, University of Tokyo, Tokyo 113-8656, Japan; Electron Microscopy Laboratory, and International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China; Collaborative Innovation Center of Quantum Matter, Beijing 100871, China. Electronic address: p-gao@pku.edu.cn.
² Institute of Engineering Innovation, School of Engineering, University of Tokyo, Tokyo 113-8656, Japan.
³ Institute of Engineering Innovation, School of Engineering, University of Tokyo, Tokyo 113-8656, Japan; Nanostructures Research Laboratory, Japan Fine Ceramic Center, Nagoya 456-8587, Japan.
⁴ Institute of Engineering Innovation, School of Engineering, University of Tokyo, Tokyo 113-8656, Japan; Nanostructures Research Laboratory, Japan Fine Ceramic Center, Nagoya 456-8587, Japan; Elements Strategy Initiative for Structural Materials, Kyoto University, Kyoto 606-8501, Japan. Electronic address: ikuhara@sigma.t.u-tokyo.ac.jp.

PMID: 28985625
DOI: 10.1016/j.ultramic.2017.09.006

Abstract

By using the state-of-the-art microscopy and spectroscopy in aberration-corrected scanning transmission electron microscopes, we determine the atomic arrangements, occupancy, elemental distribution, and the electronic structures of dislocation cores in the 10° tilted SrTiO₃ bicrystal. We identify that there are two different types of oxygen deficient dislocation cores, i.e., the SrO plane terminated Sr_0.82Ti_0.85O_3-x (Ti^3.67+, 0.48 ≤ x ≤ 0.91) and TiO₂ plane terminated Sr_0.63Ti_0.90O_3-y (Ti^3.60+, 0.57 ≤ y ≤ 1). They have the same Burgers vector of a[100] but different atomic arrangements and chemical properties. Besides the oxygen vacancies, Sr vacancies and rocksalt-like titanium oxide reconstruction are also identified in the dislocation core with TiO₂ plane termination. Our atomic-scale study reveals the true atomic structures and chemistry of individual dislocation cores, providing useful insights into understanding the properties of dislocations and grain boundaries.

Keywords: Aberration corrected transmission electron microscopy; Annular bright field (ABF); Atomically resolved EDS; Dislocations; SrTiO(3).

Publication types

Research Support, Non-U.S. Gov't