TILING OF CANONICAL CELLS - ALMNSI QUASI-CRYSTAL MODEL

A deterministic 'canonical tiling' model is presented of the icosahedr al quasicrystal AlMnSi, which incorporates three important features: ( i) the icosahedral clusters are linked exclusively through the twofold and threefold icosahedral directions, as suggested by the structure o f the alpha-AlMnSi phase, (ii) the structure of the cluster's third sh ells is respected, and (iii) the network of cluster centers forms the tiling of four cells. The fraction of 'glue' atoms that do not belong to any of the clusters is reduced to about 4% and the density perfectl y agrees with the experimental value.