Title of article :
Aluminium adsorption on Ir(1 1 1) at a quarter monolayer coverage: A first-principles study
Author/Authors :
Hong Zhang، نويسنده , , Aloysius Soon، نويسنده , , Bernard Delley، نويسنده , , Catherine Stampfl، نويسنده ,
Issue Information :
روزنامه با شماره پیاپی سال 2008
Pages :
4
From page :
7655
To page :
7658
Abstract :
We present an ab initio density-functional study for aluminium adsorption on Ir(1 1 1) at high symmetry sites, namely, the fcc-, hcp-hollow, top and bridge sites. In each case, we calculate the atomic geometry, average binding energy, work function, and surface dipole moment at the coverage of 0.25 monolayer. We find the favourable structure to be Al at threefold hcp-hollow site, with a corresponding binding energy of 4.46 eV. We present and compare the electronic properties of the two lowest energy structures, i.e., at the threefold hollow sites and discuss the nature of the Al–Ir bond and binding site preference. In particular, we observe a large hybridization of Al-3s, 3p and Ir-5d states near Fermi level, forming an inter-metallic bonds. This results in a significant electron transfer from the Al atoms to the Ir(1 1 1) substrate, inducing an outward pointing surface dipole moment and a large decrease in the work function of 1.69 eV for Al in the hcp-hollow site. Compared to the fcc-hollow site, adsorption in the hcp-hollow site results in a lower density-of-states at the Fermi level, as well as a greater hybridization in the bonding states.
Keywords :
Binding energy , Aluminium adsorption , Work function , Density-functional theory , Iridium
Journal title :
Applied Surface Science
Serial Year :
2008
Journal title :
Applied Surface Science
Record number :
1009770
Link To Document :
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