An ordered arrangement of atom columnar clusters in a pentagonal quasiperiodic lattice of an Al-Ni-Co decagonal quasicrystal

The structure of an AI-Ni-Co decagonal quasicrystal (called the S1-type sup erstructure), which shows diffraction patterns with superlattice reflection s, has been studied by atomic-scale observations of electron microscopy. Th e structure of the decagonal quasicrystal can be characterized as an ordere d arrangement of two kinds of atom columnar cluster with different directio ns of pentagonal symmetry. A fundamental lattice, which is constructed by c onnecting all the atom dusters, shows st pentagonal quasiperiodic lattice w ith a bond length of about 2 nm. The pentagonal lattice is divided into two superlattices, which are constructed by connecting atom clusters with the same directions of pentagonal symmetry, with a bond length of 2 tau nm (tau is the golden ratio).