Article Dans Une Revue IOP Conference Series: Materials Science and Engineering Année : 2020

Single crystal growth, crystal structure and surface characterisation of the binary phase Al45Cr7.

Pascal Boulet
Marie-Cécile de Weerd
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Emilie Gaudry
Julian Ledieu
Vincent Fournée

Résumé

A single crystal of the Al45Cr7 crystalline approximant has been grown using the Czochralski method. The structure of this phase has been resolved in the C2/m space group. Chromium atoms are systematically surrounded by Al atoms forming a distorted icosahedron. The icosahedra are linked either by a vertex or a triangular face or overlap along a five-fold axis. The (010) surface of this single crystal has been investigated under ultrahigh vacuum and shows a (1x1) termination at specific bulk planes. The terraces have a nanostructured appearance which is ascribed to the preservation of the CrAl12 clusters at the surface. Ab initio calculations shows the presence of a deep pseudogap at the Fermi level, due to both a Hume-Rothery effect combined with strong spd hybridization. The isoelectronic charge densities highlight the fact that the charges are mainly confined within the CrAl12 icosahedron providing support to a certain stability of the clusters which could explain the nanostructured surface morphology encountered. First results on Al thin film deposition on the (010) surface are also reported.

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hal-02360341 , version 1 (14-02-2020)

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Pascal Boulet, Marie-Cécile de Weerd, Emilie Gaudry, Julian Ledieu, Vincent Fournée. Single crystal growth, crystal structure and surface characterisation of the binary phase Al45Cr7.. IOP Conference Series: Materials Science and Engineering, 2020, Journal of Physics: Conference Series, 1458, pp.012016. ⟨10.1088/1742-6596/1458/1/012016⟩. ⟨hal-02360341⟩
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