Amplitude Contrast Imaging in High-Resolution Transmission Electron Microscopy of Ferroelectric Superlattice Film

TL;DR

This paper introduces a novel amplitude contrast imaging mode in high-resolution transmission electron microscopy, utilizing chromatic aberration correction to directly visualize atomic structures and distinguish light and heavy elements in ferroelectric superlattices.

Contribution

The authors demonstrate for the first time the use of chromatic aberration correction to achieve amplitude contrast imaging, enabling direct atomic visualization in complex oxide superlattices.

Findings

Successful visualization of atomic structure in BaTiO3/CaTiO3 superlattice

Discrimination between Ba and Ca atomic columns

Visualization of oxygen octahedral tilt related to ferroelectricity

Abstract

To date, high-resolution electron microscopy has largely relied on using the phase of the exit wave function at the exit surface to form a high-resolution electron microscopic image. We have for the first time used chromatic aberration correction to implement a new imaging mode to achieve amplitude contrast imaging in high-resolution electron microscopy, allowing us to obtain directly interpretable high-resolution electron microscopic images with discrimination between light and heavy atomic columns. Using this imaging approach, we have successfully visualized the atomic structure in a BaTiO3/CaTiO3 superlattice with high spatial accuracy and discrimination between Ba and Ca columns, providing direct visualization of the Ca and Ba associated oxygen octahedral tilt that controls ferroelectric behavior in these superlattice structures. Furthermore, this approach offers new opportunities to unravel the structure in a wide range of materials, especially complex oxides with exotic behaviors based on specific structural arrangements.