The intra-row diffusion of Au atoms on the (111)-(5 x 2)Au reconstructed surface was studied by means of high-temperature scanning tunnelling microscopy. It was concluded that loosely bonded Au atoms, which were arranged with 2(n+1)a spacings at room temperature, diffused in the 2-fold direction at higher temperatures among adsorbed sites which were arranged at intervals of 2a. It was suggested that these diffusing Au atoms were responsible for the presence of a non-integral number of Au atoms in the (5 x 2) unit cell.

T.Hasegawa, S.Hosoki: Physical Review B, 1996, 54[15], 10300-3