Characterizing oxygen atoms in perovskite and pyrochlore oxides using ADF-STEM at a resolution of a few tens of picometers

Abstract

This is a repository copy of Characterizing oxygen atoms in perovskite and pyrochlore oxides using ADF-STEM at a resolution of a few tens of picometers.

Influence of Light Atoms on Quantification of Atomic Column Positions in Distorted Perovskites with HAADF-STEM

“…A recent study combining multislice simulation and experimental HAADF-STEM showed that channeling can cause unintuitive contrast in noncoherently stacked heavy atomic columns based on crystal thickness and lateral separation of atomic sites . Other studies have shown that light species, such as oxygen, in columns near heavy atomic columns can affect the radial intensity profile and even the shape of the heavy atomic column. − Here, we show experimentally that cation sites in a distorted perovskite oxide crystal can appear to be displaced by several picometers from their true positions in HAADF-STEM due to coherently displaced oxygen atoms in the same atomic columns. We then examine the channeling behavior that causes the apparent displacement using multislice simulations and consider ways to mitigate or avoid the artifact.…”