Within the framework of density functional theory and the pseudopotential method, calculations of the density of electronic states of the system “Si(100) substrate plus disordered two-dimensional metal layers (Li, Be or Al)” with a thickness of one to four single-atomic layers were carried out during growth at 0°K.

It is shown that the electronic structure of the first single-atomic layers of these metals on Si(100) has band gaps. The maximum band gap was found in the Be-Si system (1.03 eV for a single-atomic layer). In this system, the band gap disappears when four single-atomic layers are deposited. In the Li-Si system (0.98 eV for a single-atomic layer) it disappears for two single-atomic layers. In the Al-Si–system (0.50 eV with four single-atomic layers), the band gap disappears for three single-atomic layers. This behavior of the band gap can be explained by the passivation of the substrate surface states and the peculiarities of the electronic structure of the adsorbed metals.