Berlin 2008 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 21: Quasicrystals

MM 21.2: Vortrag

Dienstag, 26. Februar 2008, 12:00–12:15, H 0111

Are the Al atoms correctly placed in the models of i-AlPdMn and i-AlCuFe? — •Zorka Papadopolos¹, Oliver Gröning², and Roland Widmer² — ¹Institut für Theoretische Physik, Univ. Tübingen, Germany — ²Material Science and Technology, EMPA, Thun, Switzerland

The model M(T^*(2F)) ^[1], as a model of atomic positions describes Al₇₀Pd₂₁Mn₉ and Al₆₂Cu_25.5Fe_12.5 ^[2]. The model is based on the diffraction results ^[3,4]. In the model we study the bulk terminations as defined in ^[5], through a generalisation of the Bravais’ rule to the quasicrystals. Assuming the model independent results of LEIS (low energy ion scattering) ^[6], from the STM (scanning tunnelling microscopy) simulations ^[7] on the 5fold surface, compared to the real images of i-AlPdMn, we conclude that either the Al atoms are not correctly placed in the model, or the shape of atomic surfaces, i.e. the model of atomic positions itself must be changed.

[1] http://www.quasi.iastate.edu/Structure%20Dbase%20Info.html

[2] V. Elser, Philos. Mag. B 73, (1996) 641.

[3] M.de Boissieu et al., J. Phys.: Condens. Matter 6, (1994) 10725.

[4] A. Katz et al., in Proc. of the 5th Int. Conf. on Quasicrystals, ed. C. Janot et al., (World Scientific, Singapore, 1995) p. 164.

[5] Z. Papadopolos and G. Kasner, Phys. Rev. B 72 (2005) 094206.

[6] R. Bastasz et al., Philos. Mag. 86, (2006) 855.

[7] J. Tersoff and D.R. Haman, Phys. Rev. B 31, (1985) 805.