title: Ho arrangement in the Zn6Mg3Ho icosahedral quasicrystal studied by atomic-resolution Z-contrast STEM.
abstract: The atomic structure of the Zn6Mg3Ho icosahedral quasicrystal has been studied by high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) with Z-contrast (Z: atomic number). We demonstrate that in particular Z-contrast imaging is quite powerful for specifying heavy atom positions in the quasicrystalline compound, as shown by a comparison with high-resolution phase-contrast imaging. It is confirmed that the observed Z-contrast images are fairly well explained by the projected potential of only the Ho atomic arrangement, which was recently proposed by X-ray diffraction analysis; Ho occupies an even-body-center site of the 3-dimensional Penrose lattice. Consequently, the present direct structural observation strongly supports the validity of the proposed Ho site.
authors.affiliation: National Institute for Materials Science, Tsukuba, Japan. abe.eiji@nims.go.jp
authors.forename: E
authors.initials: E
authors.lastname: Abe
authors.forename: H
authors.initials: H
authors.lastname: Takakura
authors.forename: A P
authors.initials: AP
authors.lastname: Tsai