METALLIC CHARACTER OF THE K/SI(100)-(2X1) INTERFACE AT SATURATION COVERAGE - A MOTT-HUBBARD MODEL CALCULATION OF ITS NEAR-FERMI-LEVEL BAND STRUCTURE

摘要

Recent experiments that probe the Fermi surface and the electronic structure near the Fermi level of K/Si(100)-(2x1) interfaces at saturation coverage have shown a metallic interface. These experiments are here discussed in the light of a two-dimensional Mott-Hubbard model. Our calculated band structure is consistent with them. Specifically it is shown that, by withdrawing a small amount of the (itinerant) electron charge from the interface, one obtains an empty potassium band and an almost full pi*Si band that shows a hole pocket at Gamma, in close agreement with the experimental results. If all the electron charge were assumed itinerant, one would obtain instead a full Si band and a semiconducting interface. [References: 29]