METHOD OF DETERMINING TIP STRUCTURE IN ATOMIC FORCE MICROSCOPY

The stability of single atomic tip is tested using molecular-dynamics simulation. Many metallic single-atomic tips are unstable during the scan at a tip load well below typical experimental values. For the bcc W(111) tip, second-layer-tip-atomic contributions are comparable to the first-layer contribution. These results suggest that experimentally multiple-atom tips are involved in the scanning process. We propose a method to identify tip size and structure during the scanning process. The resultant images for a number of commonly used tip materials are interpreted and compared to experiments.