Structural and electronic properties of the quasi-one-dimensional metallic chains of the Au-induced facets on the Si(5 5 12) surface

We have investigated the atomic arrangements and electronic properties of the quasi-one-dimensional (Q1D) atomic chains of the Au-induced facets formed on the clean Si(5 5 12)-2×1 surface. The interchain distances of the two well ordered facet structures are estimated to be 30.2 and 22.8. By utilizing linearly polarized synchrotron photons, we also determine a complete band diagram of the surface bands and their symmetry characteristics along the two high symmetry azimuths (Γ-M̄ and Γ-X̄) of the surface Brillouin zone. The Q1D nature of the Au-induced atomic chains has been well demonstrated by the extremely anisotropic band dispersions of the Au-induced surface bands in addition to the 2×1 surface morphology. We find that while the clean reconstructed Si(5512)-2×1 surface is insulating, the Au-induced chains form a highly anisotropic metallic system.