Semiconductor-metal transition of the single-domainK/Si(100)−(2×1)interface by Fermi-surface determination

The semiconductor-metal electronic transition of the $\mathrm{K}/\mathrm{S}\mathrm{i}\mathrm{}\left(100\right)-(2\mathrm{}\times 1)$ interface is studied by exploring the Fermi surface with photoemission spectroscopy. Once metallized at a critical coverage the surface remains metallic up to saturation. The experimentally determined Fermi surface consists of hole pockets centered around the $\overline{\Gamma }$ points of the surface Brillouin zone. These results are fairly well reproduced by calculations based on a 2D Mott-Hubbard model. The metallization process is related to the overlap of Si-confined electron clouds surrounding the K atoms rather than to changes in the surface atomic structure.