Quasiperiodic superstructure with an ordered arrangement of atom columnar clusters in an Al-Ni-Ru decagonal quasicrystal with 0.4 nm periodicity

We have found a highly perfect quasiperiodic superstructure of a decagonal quasicrystal (D-phase), which is formed bi the ordered arrangement of atom columnar clusters. The D-phase with 0.4 nm periodicity, which has been foun d in a conventionally solidified Al70Ni20Ru10 alloy, shows many superlattic e reflections in its tenfold electron diffraction pattern. High-resolution electron microscopy of the D-phase reveals that the ordered arrangement of two types of atom columnar clusters with different directions of pentagonal symmetry allows the fundamental lattice of a pentagonal tiling to be subdi vided into two sublattices of rhombic tilings with edge length enlarged tau times (tau is the golden ratio).