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Structure of the orthorhombic Al 13 Co 4 (100) surface using LEED, STM, and ab initio studies

2011; American Physical Society; Volume: 84; Issue: 8 Linguagem: Inglês

10.1103/physrevb.84.085411

1550-235X

Heekeun Shin, K. Pussi, Émilie Gaudry, J. Ledieu, V. Fournée, Sebastián Alarcón Villaseca, Jean‐Marie Dubois, Yu. Grin, P. Gille, W. Moritz, Renee D. Diehl,

Boron and Carbon Nanomaterials Research

In a combined scanning tunneling microscopy (STM), low-energy electron diffraction (LEED), and density functional theory (DFT) study of the surface of Al${}_{13}$Co${}_{4}$(100), all techniques have found that after annealing to 1165 K, the surface structure is consistent with a dense Al-rich plane with surface Co atom depletion. Various structure models were considered, and in the LEED study, the best agreement was found with a model that consists of Al-rich terminating planes with no Co atoms, and otherwise a structure similar to the bulk puckered layers. This structure was also found to be stable in the DFT study. The best-fit structural parameters are presented for the two domains of this structure, which contain bipentagons that can be related to the pentagonal bipyramidal structures in the bulk, plus additional glue atoms between them. These domains are not strictly related to each other by symmetry, as they have different surface relaxations. The STM study found significant differences in the surfaces of samples grown by different methods and is able to explain a different interpretation made in an earlier study.