Atomic-Scale Structure Relaxation, Chemistry and Charge Distribution of Dislocation Cores in SrTiO3

TL;DR

This study uses advanced microscopy to reveal atomic structures, chemistry, and charge distribution of dislocation cores in SrTiO3, uncovering two distinct oxygen-deficient core types with different atomic arrangements and chemical properties.

Contribution

It provides the first atomic-scale characterization of dislocation cores in SrTiO3, identifying their structures, chemistry, and electronic properties with high precision.

Findings

Two types of oxygen deficient dislocation cores identified

Different atomic arrangements and chemical properties observed

Presence of vacancies and reconstruction in dislocation cores

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{\deg}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.