Regensburg 2002 – scientific programme

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O: Oberflächenphysik

O 12: Struktur und Dynamik reiner Oberfl
ächen

O 12.6: Talk

Monday, March 11, 2002, 16:30–16:45, H45

Investigation of the 10-fold Decagonal-AlNiCo Surface by Low Temperature Scanning Tunneling Microscopy — •H. R. Sharma¹, K. J. Franke¹, W. Theis¹, S. Fölsch¹, P. Gille², and K. H. Rieder¹ — ¹Fachbereich Physik der Freien Universität Berlin — ²Ludwig-Maximilians-Universität München

Although many aspects of the bulk structure of decagonal quasicrystals are well understood, knowledge regarding their surface is much more limited. Employing low temperature scanning tunneling microscopy (LT-STM), we have investigated the structure and morphology of the 10-fold surface of d-Al_71.8Ni_14.8Co_13.4. The STM images show a high density of rough steps without the tendency of step pairing. The measured monoatomic step height of 2Å corresponds to half of the periodicity along the 10-fold axis. Two kinds of surface terminations were observed in a single terrace. The terraces show 5-fold symmetric motives, which have opposite orientation with respect to those on the adjacent terraces. Position and distances of the repeating 5-fold motives indicate that the cluster model of the bulk is also extended up to the surface. The Fourier transform of the structure has 10-fold symmetry which agrees with the SPA-LEED pattern.