Tendency in tip polarity changes in non-contact atomic force microscopy imaging on a fluorite surface

Area of Science:

• Materials Science
• Surface Science
• Nanotechnology

Background:

• Non-contact atomic force microscopy (NC-AFM) is a powerful tool for atomic-scale surface imaging.
• The CaF₂(111) surface exhibits unique contrast patterns crucial for understanding NC-AFM mechanisms.
• Tip-sample interactions are critical for contrast formation in NC-AFM.

Purpose of the Study:

• To investigate how tip changes affect atomic contrast in NC-AFM of CaF₂(111).
• To differentiate between polarity-changing and polarity-preserving tip alterations.
• To identify tip configurations conducive to stable CaF₂(111) imaging.

Main Methods:

• Analysis of atomic contrast variations in a large dataset of NC-AFM images.
• Correlation of observed contrast changes with tip termination characteristics.
• Utilizing established understanding of CaF₂(111) contrast patterns for tip identification.

Main Results:

• Atomic contrast changes are attributed to tip-terminating cluster polarity shifts or atom rearrangements.
• Polarity-preserving and polarity-changing tip changes can be unambiguously identified on CaF₂(111).
• The majority of tip changes observed resulted in negative tip termination.

Conclusions:

• Tip configuration plays a vital role in achieving stable NC-AFM imaging of CaF₂(111).
• Understanding tip evolution is key to reproducible atomic-scale imaging.
• A preference for negative tip termination was observed, guiding future experimental setups.