Structure of a quasicrystal without atomic clusters

We show that, using high-resolution transmission electron microscopy, the f irst Frank-Kasper decagonal quasicrystal discovered in Zn-Mg-rare-earth all oys has a novel atomic structure in which the atomic arrangement in the ten fold symmetry plane can simply be interpreted as the Penrose tiling decorat ed by individual atoms. This is in sharp contrast to the idea of linking at omic 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 conc ept is applied for the structural description.