An Atom Cluster Model of F-Type Icosahedral Quasicrystals, Derived from the Structure of 1/1 Cubic Approximant Phase (α-(AlPdMnSi))

We propose an atom cluster model of F-type icosahedral quasicrystals based on the structure of an α-(AlPdMnSi) phase, which is a p/q = 1/1 cubic approximant of icosahedral quasicrystals. In the model, large dodecahedral and small icosahedral atom clusters, which are located at the (1/2,1/2,1/2) and (0,0,0) positions in the α-(AlPdMnSi) structure, respectively, are placed at twelvefold sites classified into two groups in the three-dimensional Penrose lattice. A diffraction pattern of this model reproduces well the characteristic features of an electron diffraction pattern of the F-type Al-Pd-Mn icosahedral quasicrystal.