Figure 2
Calculated surface band structures of (a) the p(2 × 1) and (b) c(4 × 2) structures. The bands projected onto the px, py, and pz orbitals of Si-dimer atoms are displayed with circles whose radii are proportional to the weights of such orbitals. The energy zero represents EF. The inset in (a) shows the surface Brillouin zones of the p(2 × 1) and c(4 × 2) unit cells. The total DOS and the local DOS of Si dimers are displayed with solid and dotted lines, respectively. The charge characters of the π and π* surface states at the Γ point are drawn with an isosurface of 0.05 e/Å, while that of the bulk state of c(4 × 2) at the Γ point (just below EF) is drawn with an isosurface of 0.02 e/Å.
