X-ray photoelectron diffraction on the 6-fold (001) μ-Al₄Mn approximant surface

Abstract

In theoretical investigations, the study of the properties of quasicrystals via analysis of periodic approximant structures has proven to be very successful. We performed experimental surface structure studies on the μ-Al₄Mn approximant, exhibiting a large unit cell of 563 atoms, to get on to the origin of the unusual physical properties of complex quasicrystalline systems. The 6-fold (001) μ-Al₄Mn surface was investigated by surface-sensitive low energy electron diffraction and X-ray photoelectron diffraction. Detailed analysis of the experimental data using single scattering cluster calculations revealed a pure bulk truncated surface, which is cut at the z = c/2 and 3c/4 layers of the unit cell, with a slight preference for the z = 3c/4 termination. The possibility of preparing well ordered, bulk terminated surfaces of such a complex, yet periodic, crystal structure in the Al–Mn system allows the application of a wealth of surface analytical tool to obtain a greater understanding of the physical properties of complex metallic alloys in relation to quasicrystals.

Keywords:

• aluminium alloys
• aperiodic materials
• approximants
• intermetallic alloys
• photoelectron spectroscopy
• quasicrystals
• structure
• surface analysis

Acknowledgements

The Swiss National Foundation (contract number SNF 200021-112333/1) and the European Network of Excellence (NoE): ‘Complex Metallic Alloys’ CMA (contract number NoE 500140) is acknowledged.