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Sub-nanometer Resolution Imaging with Amplitude-modulation Atomic Force Microscopy in Liquid
Published on: December 20, 2016
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Coupled Compositional and Displacive Modulations in KLaMnWO6 Revealed by Atomic Resolution Imaging
Susana Garcia-Martin1, Graham King2, Esteban Urones-Garrote1
1Departamento de Química Inorgánica. Facultad de Ciencias Químicas. Universidad Complutense, Madrid 28040, Spain.
Journal of the American Chemical Society
|November 3, 2021
Summary
Complex crystal modulations in KLaMnWO6 were imaged using scanning transmission electron microscopy (STEM). This reveals coupled compositional and octahedral tilting variations within the perovskite structure.
Area of Science:
- Materials Science
- Solid-State Chemistry
- Crystallography
Background:
- Potassium lanthanum manganese tungstate (KLaMnWO6) exhibits complex structural properties.
- Cation vacancies stabilize the oxide, leading to a specific stoichiometry (La1+K1-MnWO6).
Purpose of the Study:
- To investigate the intricate compositional and displacive modulations in KLaMnWO6 at atomic resolution.
- To elucidate the relationship between compositional variations and structural distortions.
Main Methods:
- Atomic resolution imaging using scanning transmission electron microscopy (STEM).
- High-angle annular dark-field STEM (HAADF-STEM) for compositional mapping.
- Annular bright-field STEM (ABF-STEM) for anion sublattice visualization.
Main Results:
- Detailed imaging of complex compositional modulations in both potassium and lanthanum layers.
- Coupling observed between compositional modulation in the lanthanum layer and octahedral tilting.
- Modulations are accommodated within a specific supercell of the perovskite-type structure (5√2ap × 5√2ap × 2ap).
Conclusions:
- STEM provides unprecedented atomic-scale insight into complex modulated structures.
- The findings reveal a sophisticated interplay between composition and structure in KLaMnWO6.
- Understanding these modulations is crucial for predicting and controlling material properties.
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