Atomic-Resolution Imaging of Aragonite (001) Surface in Water by Frequency Modulation Atomic Force Microscopy

摘要

Aragonite is a high-pressure phase of calcium carbonate crystals. However, aragonite is formed under normal pressure with the help of biomineralization. Although it is important to observe growth features to understand the growth mechanism of the aragonite surface, only a few research groups have succeeded in observing the growth steps. In this study, we performed observation of the (001) face of a natural aragonite crystal surface at the atomic scale by the newly developed frequency modulation atomic force microscopy (FM-AFM). On the (001) face of aragonite, several growth islands with flat terraces were observed. We have succeeded in obtaining atomic-resolution images of the pseudo-hexagonal arrangement of calcium ions on the terraces. We also obtained atomic-resolution images on the calcite (1014) face by FM-AFM. which highlights the difference in the surface atomic arrangements of the two polymorphs was clearly visualized.