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

The structure of an Al-Ni-Co decagonal quasicrystal (called the S1-type superstructure), which shows diffraction patterns with superlattice reflections, has been studied by atomic-scale observations of electron microscopy. The structure of the decagonal quasicrystal can be characterized as an ordered arrangement of two kinds of atom columnar cluster with different directions of pentagonal symmetry. A fundamental lattice, which is constructed by connecting all the atom clusters, shows a pentagonal quasiperiodic lattice with 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