High-resolution electron-microscopy study and structure modeling of the stable decagonal Al-Cu-Co quasicrystal

Abstract

We report the observation of a spatial quasiperiodicity in high-resolution electron-microscope images of the thermodynamically stable decagonal ${\mathrm{Al}}_{65}$${\mathrm{Cu}}_{15}$${\mathrm{Co}}_{20}$ quasicrystal. Well defined quasiperiods consistent with decagonal symmetry and x-ray-diffraction data have been found. The structure observed is inconsistent with conventional ideal Penrose tiling. There is strong evidence for an entropy stabilization mechanism.