Step-terrace morphology and reactivity to C60 of the five-fold icosahedral Ag-In-Yb quasicrystal

P. J. Nugent, J. A. Smerdon, R. McGrath, M. Shimoda, C. Cui, A. P. Tsai, H. R. Sharma

Research output: Contribution to journalArticlepeer-review

9 Citations (Scopus)

Abstract

The surface of the icosahedral i-Ag-In-Yb quasicrystal provides one of the first non-Al-based aperiodic surfaces that is suitable for study under ultra-high vacuum conditions. We present a scanning tunnelling microscopy (STM) study of the five-fold surface of this new quasicrystal demonstrating detailed structure of the terraces and steps. The analysis of the autocorrelation functions of STM images at opposite bias polarities and of the in-plane structure of the bulk model of i-Cd-Yb, which is isostructural to i-Ag-In-Yb, reveals that the surface terminations occur at the centres of the rhombic triacontrahedral (RTH) clusters, which are the basic building blocks of this material. The study further confirms that the unoccupied electronic states are located on Yb sites. Step edges display a Fibonacci sequence of truncated clusters, which can also be explained in terms of the model structure. Occasionally, a single terrace is found to display different structures at negative bias, whereas the same terrace shows a uniform structure at positive bias. Depositing C60 creates a disordered overlayer on the surface with no resulting FFT or LEED patterns.

Original languageEnglish
Pages (from-to)2862-2869
Number of pages8
JournalPhilosophical Magazine
Volume91
Issue number19-21
DOIs
Publication statusPublished - 2011 Jul 1

Keywords

  • Ag-In-Yb
  • C
  • Fibonacci sequence
  • autocorrelation
  • bias dependence
  • quasicrystal
  • scanning tunnelling microscopy
  • surface morphology

ASJC Scopus subject areas

  • Condensed Matter Physics

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