ADHESION IN ATOMIC-SCALE METAL CONTACTS

The adhesion interaction of an Ir tip with Ir and Al surfaces has been investigated using the scanning tunneling microscope. Qualitative dif ferences in the adhesion characteristics have been observed. A cluster model based on effective pair potentials has been set up to understan d adhesion in atomic-scale contacts. The model calculation provides a semi-quantitative explanation of the experimental data. In particular, it is shown that subtle differences of the atomic-interaction potenti als have a significant effect on the contact mechanics.