Figure 8
STM images of the Si(001)- c (8 × n ) surface: (a) empty states (+1.7 V, 150 pA) and (b) filled states (-2.2 V, 120 pA). Corresponding schematic drawings of the surface structure are superimposed on both pictures. The lighter circle the higher the corresponding atom is situated in the surface structure. The dimer buckling is observed in the filled state image (b), which is reflected in the drawing by larger open circles representing higher atoms of the tilted Si dimers of the uppermost layer of the structure.