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

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 degrees tilted SrTiO3 bicrystal. We identify that there are two different types of oxygen deficient dislocation cores, i.e., the SrO plane terminated Sr0.82Ti0.85O3-x (Ti3.67+, 0.48 <= x <= 0.91) and TiO2 plane terminated Sr0.63Ti0.90O3-y (Ti3.60+, 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. (C) 2017 Elsevier B.V. All rights reserved.