Univ. Paris-Saclay

Service de Physique de l'Etat Condensé

Reconstruction on the Al2Cu (001) surface led by covalent bonding
Laura N. Serkovic Loli
CSIC - Univ.del Pais Vasco, San Sebastian, Spain
et Institut Jean Lamour (UMR7198 CNRS), Nancy, France
Mardi 02/10/2012, 14:00
SPEC Salle Itzykson, Bât.774, Orme des Merisiers

Surface reconstructions are generally observed on covalently bonded materials, and they are not frequent on metal surfaces. Recently, quantum calculations on the Al2Cu metallic alloy identified covalent-like Al-Al bonds [1]. In this study, we show that these covalent bondings are at the origin of a surface reconstruction for Al2Cu(001) [2]. The bulk structure of the Al2Cu intermetallic compound is described by graphite-like Al 63 nets [3]. The combination of both experimental methods (STM, STS, LEED, UPS, XPS) and ab-initio computational methods (atomic relaxations, STM simulations, electronic structure calculations) gives many arguments to match the surface plane with a bulk truncated surface model terminated by incomplete Al planes. The covalent-like interaction is highlighted by ab-initio calculations: the energetic cost associated with the removal of pairs of Al atoms is the lowest for the two nearest surface Al atoms.

[1] Yu. Grin et al., J. Sol. St. Chem. 179 (2006) 1707.
[2] L.N. Serkovic Loli et al., Phys. Rev. Lett. 108 (2012) 146101.
[3] H. Nowotny and K. Shubert, Z. Metallkd. 37 (1946) 17.

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