Quantitative structural analysis of twin boundary in alpha-Zn7Sb2O12 using HAADF STEM method

Area of Science:

• Materials Science
• Crystallography
• Solid-State Chemistry

Background:

• Twin boundaries significantly influence material properties.
• Understanding atomic structure and composition at interfaces is crucial for materials design.
• alpha-Zn7Sb2O12 is a complex oxide with potential applications.

Purpose of the Study:

• To determine the atomic structure and composition of the 1/4{110} twin boundary in alpha-Zn7Sb2O12.
• To investigate atomic site shifts and elemental distribution across the twin boundary.
• To provide precise experimental data for validating atomistic simulations.

Main Methods:

• Quantitative high-angle annular dark field scanning transmission electron microscopy (HAADF STEM) for atomic-resolution imaging.
• Maximum entropy method and averaging for noise reduction in experimental images.
• Experimentally determined parameters for dynamical simulations to interpret HAADF STEM data.

Main Results:

• Octahedral sites at the twin boundary exhibit a slight shift parallel to the [110] direction.
• A notable reduction in antimony (Sb) concentration was detected at octahedral sites adjacent to the twin boundary.
• Measured Sb concentrations at specific regions were 4 ± 3%, 8 ± 3%, and 19 ± 2% (starting from 33 at%).

Conclusions:

• The study precisely characterized the atomic arrangement and chemical composition at the 1/4{110} twin boundary in alpha-Zn7Sb2O12.
• The observed Sb deficiency at the twin boundary is a key structural feature.
• These findings offer critical insights into the behavior of complex oxides at interfaces.