RHEED and STM studies of the pseudo-tenfold surface of the ξ′-Al77.5Pd19Mn3.5 approximant crystal

H. R. Sharma, M. Shimoda, V. Fournée, A. R. Ross, T. A. Lograsso, A. P. Tsai

Research output: Contribution to journalArticlepeer-review

18 Citations (Scopus)

Abstract

The pseudo-tenfold surface of the ξ′-Al77.5Pd19Mn3.5 crystal, an approximant of the icosahedral Al-Pd-Mn quasicrystal, is investigated by reflection high-energy electron diffraction (RHEED) and scanning tunneling microscopy. The observed RHEED patterns of the surface after sputtering are found to be consistent with those of a simple cubic lattice with (11̄0) surface plane. The [001] and [110] axes of the surface plane are oriented along the principal low-index axes of the bulk. The RHEED patterns of the sputter-annealed surface consist of diffraction streaks with periodic spacings expected for the bulk truncated surface. The surface prepared under different preparation methods is found to exhibit different step-height distribution and terrace morphology. A longer annealing yields a high density of shallow pentagonal pits on terraces, separated predominantly by 0.80-nm high steps and occasionally by double steps. In contrast, the surface prepared with shorter annealing time exhibits highly perfect terraces with 0.80-nm-high steps and additional unusual steps of heights close to 0.40nm. All step heights observed for both preparation methods are consistent with interlayer spacings of the bulk model.

Original languageEnglish
Article number224201
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume71
Issue number22
DOIs
Publication statusPublished - 2005 Jun 1

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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