4' Summary, conclusions, opportunities

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4. Summary, conclusions, opportunities
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Clean surfaces Numbers
75 studies of clean quasicrystal surfaces 6
studies of clean giant unit cell surfaces
Euroschool08 McGrath 4. Summary
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Clean surfaces - summary

• Successes
• Preparation techniques for clean flat surfaces
• Equivalence with bulk terminations
• Extensive semi-quantitative studies, especially
  with STM
• Progress with technique development esp. LEED,
  DFT
• Shortcomings
• Paucity of quantitative studies
• Restriction to Al-based materials
• Opportunities
• Non Al-based materials!
• More quantitative studies using e.g. SXRD, LEEM,
  PhD

Euroschool08 McGrath 4. Summary
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Adsorbates numbers

• 54 studies of adsorbates on quasicrystals
• 4 studies of adsorbates on giant unit cell
  surfaces

Euroschool08 McGrath 4. Summary
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Metal growth 3 possibilities in epitaxy

• Intermixing (I)
• Adsorbate forms a surface alloy
• Rotational epitaxy (RE)
• Crystalline growth with orientational
  relationships to substrate
• Pseudomorphic growth (P)
• Film adopts a new structure defined by the
  substrate
• Multilayer modulated (MLM)

Euroschool08 McGrath 4. Summary
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Adsorbates on quasicrystals
Euroschool08 McGrath 4. Summary
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Adsorbates on quasicrystals
Euroschool08 McGrath 4. Summary
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Adsorbates on quasicrystals
Smerdon et al. JPCM 2008 in press
Euroschool08 McGrath 4. Summary
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Adsorbates - summary

• Successes
• Enhanced understanding of epitaxy
• Demonstration of pseudomorphic monolayers/films
  on qcs
• Demonstration of quantum size effects on qc
  surfaces
• Shortcomings
• Little significant work on molecular structures
• No success in forming magnetic overlayers on qcs
• Opportunities
• Unmapped regions of the adsorbate landscape
• alkalis, rare earths, etc
• More quantitative studies using e.g. SEXAFS, PhD

Euroschool08 McGrath 4. Summary
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Structural studies of CMA surfaces Geographical
league table
Euroschool08 McGrath 4. Summary
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APERIODIC'09 International Conference on
Aperiodic Crystals
13-18 September 2009 Liverpool, UK
www.aperiodic09.org