Abstract
Atomic-scale adhesion phenomena between KBr tip and sample were studied by dynamic force spectroscopy with a small amplitude of down to at room temperature. The high-resonance frequency of the second flexural mode of a silicon cantilever () suppresses an apparent dissipation energy caused by undesirable mechanical couplings in between the cantilever and the dither piezo actuator. Further, the Joule heating dissipation contribution and the noise-equivalent dissipation energy were reduced by setting a smaller amplitude. Usage of a high resonance frequency and a smaller amplitude enables us to perform highly sensitive measurements of the atomic-scale adhesion and the tip-instability-related energy dissipation. Tip changes, caused by tip-sample interactions and thermal energy, resulted in three different dissipation energy levels (). This infrequent change of the tip apex condition often prevents a stable imaging with small amplitude. Our systematic measurement shows that the atomic adhesion is caused mainly in the tip itself, and a sharper and softer tip induced a larger energy dissipation.
4 More- Received 17 April 2012
DOI:https://doi.org/10.1103/PhysRevB.86.245419
©2012 American Physical Society