NONEMPIRICAL CLUSTER STUDY OF THE Au ADSORPTION ON THE Si(111) SURFACE

Abstract

The nonempirical discrete-variational method of local density approximation was used to study the electronic structure and the most stable position of a single Au atom for the Si(111)–Au chemisorption system. Only the symmetric adsorption sites (H3, T4, "on-top") were considered. The three fold hollow site has been found to be energetically the most favorable position with the vertical distance between adsorbed Au atom and the topmost silicon atom plane of 1.59 Å, binding energy of 4.76 eV and vertical vibrational mode of 87 cm –1. The photoemission spectra were calculated and compared with the experimental spectra. Although the calculations suggest that Au atom can not penetrate under the silicon surface, the possibility has been shown for Au atom to replace the surface silicon atom upon the adsorption. The results of the calculations are discussed in connection with the existing models for initial stages of the Au growth on the Si(111) surface.