Structure of a quasicrystal without atomic clusters

We show that, using high-resolution transmission electron microscopy, the first Frank-Kasper decagonal quasicrystal discovered in Zn-Mg-rare-earth alloys has a novel atomic structure in which the atomic arrangement in the tenfold symmetry plane can simply be interpreted as the Penrose tiling decorated by individual atoms. This is in sharp contrast to the idea of linking atomic clusters which have the same point symmetry as the Fourier spectrum of quasicrystals, which has been successfully used to describe the structure of quasicrystals until now. An energetically favorable quasi-unit-cell concept is applied for the structural description.