5D Modelling of decagonal Al–Co–Ni based on the W-approximant

Abstract

A structure model for decagonal Al–Co–Ni with 8 Å periodicity along the decagonal axis is proposed. The model agrees well with available experimental information, such as electron microscopic images and three-dimensional (3D) Patterson maps calculated from X-ray-diffraction data. The model is based on a novel columnar cluster with 20 Å diameter and symmetry 5/mm building the W-approximant, Al_72.5Co₂₀Ni_7.5. The proposed cluster also allows modelling of the various types of disorder and superstructures found in decagonal Al–Co–Ni.

Acknowledgement

Financial support under grant SNF 200020-105158 is gratefully acknowledged.