Space Group Determination of Decagonal Quasicrystals of an Al70Ni15Fe15 Alloy Using Convergent-Beam Electron Diffraction

Abstract
Clear space group determination of a decagonal quasicrystal has been performed for the first time by convergent-beam electron diffraction (CBED) about Al70Ni15Fe15. The space group of the alloy has been revealed to be noncentrosymmetric P m2. The alloy is the first quasicrystal to belong to a noncentrosymmetric space group, and has been found to have a lattice period of 0.4 nm in the direction of the decagonal axis, and to accompany structural modulation waves.