Figure 2: “(a) Optimized Si(553)-Au surface with Au adsorbed at the Si step edge. The surplus coverage corresponds to 1 Au per (56) unit cell, or 0.03 ML. Si is white, Au is yellow, a₀ is the Si(111) lattice constant. (b) Schematic representation of the Au chains, before and after Au adsorption, or with an antiphase segment between two idealized stacking faults.” [3].