Adhesion properties of decagonal quasicrystals in ultrahigh vacuum

Abstract

The atomic scale adhesion properties of two high-symmetry surfaces of decagonal Al-Ni-Co quasicrystals have been investigated using atomic force microscopy (AFM) in ultrahigh vacuum. Imaging the surface allowed us to distinguish the plastic regime from the elastic (reversible) regime of tip-sample contact. The work of adhesion of the atomically clean quasicrystal surface in the plastic regime is smaller than that of single crystalline Pt(111) by a factor of 10, reflecting a lower surface energy for the quasicrystal surface. However, the adhesion force must be reduced even further, in order to make measurements outside of the plastic regime possible. We present a strategy for doing this that involves chemical modification of the surface or the tip, together with appropriate choice of mechanical contact parameters.

Acknowledgement

This work was supported by the Director, Office of Energy Research, Office of Basic Energy Sciences, Materials Sciences Division, of the U.S. Department of Energy through the Ames Laboratory, Contract No. W-405-Eng-82, and through the Lawrence Berkeley National Laboratory, Contract No. DE-AC02-05CH11231.