Surface reconstruction of Au(001): High-resolution real-space and reciprocal-space inspection
Abstract
The hexagonal reconstruction of Au(001) has been a model system for the understanding of complex metal surface reconstructions, and it has been intensively studied over almost five decades. Nevertheless, details of the reconstruction regarding the top layer to substrate matching and alignment are not unambiguously identified due to restricted resolution of previously available analytical tools as well as nonuniform sample quality. We therefore quantitatively reinvestigated the system by applying high-resolution real-space and reciprocal-space inspection using scanning tunneling microscopy and spot profile analysis low-energy electron diffraction in analyzing a high-quality Au(001) sample. We show that the Au(001) reconstruction consists of two rotational domains of a commensurate c(28×48) superstructure. It results from a Moiré-like buckling of a quasihexagonal top layer which is characterized by lattice vectors having a length of 0.9655a and 0.9581a, respectively, where a is the interatomic distance of Au(001). The former vector runs exactly along [110] or [-110], whereas the latter one deviates by 59.75° from those directions. Ar+ ion bombardment at elevated temperatures induces a rotation of the top layers up to angles of ±0.83°. Sample annealing yields a turning back into the initial top layer alignment. Rotation and reorientation proceeds continuously, i.e. all angles between 0 and ±0.83° are observed. Using simple hard sphere models, the main characteristics of the reconstruction are explained. This includes even structural details of the reconstruction at step edges for nonrotated and rotated quasihexagonal top layers.
- Publication:
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Physical Review B
- Pub Date:
- July 2014
- DOI:
- 10.1103/PhysRevB.90.035446
- Bibcode:
- 2014PhRvB..90c5446H
- Keywords:
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- 68.35.-p;
- 68.37.-d;
- Solid surfaces and solid-solid interfaces: Structure and energetics;
- Microscopy of surfaces interfaces and thin films