ALUMINUM ON SI(100) - GROWTH AND STRUCTURE OF THE 1ST LAYER

The growth and the (electronic) structure of a single layer of aluminu m on the Si(100) surface are examined by means of first principles cal culations. The calculated local density of states is used to interpret e scanning tunneling microscopy data. We identify the adsorption sites that give rise to the polymerization-like one-dimensional growth of A l. The Al-induced surface states of the p (2 x 2) covered Si(100) surf ace are calculated. The surface bandgap is increased, as compared to t he clean Si(100) surface, which means that the first adsorbed Al layer passivates the surface electrically.