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

The semiconductor-metal electronic transition of the K/Si(100)-(2×1) 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 Γ̅ 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.