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Abstract

The interaction of the reconstructed Au(001)(5 × 20) surface with adsorbed K atoms was analyzed by means of scanning tunneling microscopy and low-energy electron diffraction (LEED). For K coverages < 0.1 monolayers (ML) the (5 × 20) reconstruction of the substrate is maintained. Higher K coverages lead to the formation of islands of a K-induced reconstruction whose area grows with increasing coverage. The Au(001)(5 × 20) surface reconstruction is completely lifted at 0.25 ML K, whereby in agreement with previous studies a (1 × 2) LEED pattern is observed. From the topography the surface density of Au atoms of the (1 × 2) phase is determined to be 0.5 ML. The (1 × 2) phase is interpreted as a (1 × 2) missing-row substrate structure with the K atoms adsorbed in the reconstruction troughs. Upon high-temperature annealing of the K-covered surface a complex intermixed K/Au(001) surface phase evolves.