SEM and AFM studies of a 5-fold surface of icosahedral AlPdMn

A 5-fold surface of the icosahedral AlPdMn (i-AlPdMn) quasicrystal (QC) was studied by means of scanning electron microscopy (SEM) and atomic force microscopy (AFM) under ambient conditions. We show that a very complicated inhomogeneous surface morphology may develop on the 5-fold surface prepared by ion sputtering and annealing cycles in UHV. Sputtering and sublimation both contribute to material removal on the surface. The sublimation takes place at the annealing temperature at sites of surface defects induced by mechanical polishing and sputtering in UHV. The surface is characterized by nano-sized clusters of about 40 nm in size which form terraces. Results give further evidence for the cluster-based structure of the i-AlPdMn QC.