True atomic-resolution imaging of (1014) calcite in aqueous solution by frequency modulation atomic force microscopy

Area of Science:

• Geochemistry
• Biomineralization
• Materials Science

Background:

• Calcite (CaCO3) is an abundant mineral vital to biomineralization and environmental geochemistry.
• Surface processes like dissolution, growth, and adsorption are critical for understanding calcite's role.
• Knowledge of calcite's natural surface structure in liquid environments is essential for research.

Purpose of the Study:

• To investigate the surface structure of calcite's most stable cleavage plane under liquid conditions.
• To demonstrate the high-resolution imaging capabilities of frequency modulation atomic force microscopy (FM-AFM) in liquids.
• To gain more detailed structural information beyond previously reported contrast features.

Main Methods:

• Utilized frequency modulation atomic force microscopy (FM-AFM) for surface analysis.
• Performed imaging under liquid conditions to mimic natural environments.
• Achieved true atomic-resolution imaging of the calcite (1014) cleavage plane.

Main Results:

• FM-AFM successfully provided atomic-resolution images of calcite in a liquid environment.
• Observed contrast features consistent with previous contact mode AFM studies, attributed to carbonate groups.
• Revealed additional, more detailed structural information, including the calcium sublattice of the (1014) plane.

Conclusions:

• Frequency modulation atomic force microscopy is highly effective for atomic-resolution imaging of calcite surfaces in liquids.
• The technique provides enhanced structural insights compared to previous methods.
• This study advances the understanding of calcite surface structures in relevant environmental conditions.