Phason Mechanism for Diffusion in Quasicrystalline Structures

ABSTRACT Specific properties of quasicrystals (QCs) with regards to their structures are discussed with emphasis on diffusion process. To fulfil this, regular mechanisms in the solids are introduced. The experimental results show that the predominant mechanism in quasicrystals is phason which is caused by the absence of proper matching in their structure and the vacancies in the lattice. Monolayers of Al were deposited on the surface of an i-Al-Pd-Mn quasicrystal at constant temperature and the diffusion of the elements into the surface measured by low energy ion scattering. According to our results the activation energy for Al diffusion in the i-Al-Pd-Mn quasicrystal is found to be smaller than that for Al diffusion in regular crystals. It was therefore concluded that a phason mechanism controlled the diffusion. The results of this work can be phason mechanism predominate which is agreement with the some theoretical scientists who believe to phason mechanism at least in low temperatures.