The model of the magnesium silicide phase (2/3√3×2/3√3 )-R30°on Si(111)

A structural model for two-dimensional silicide with structure (2/3√3×2/3√3)-R30°, consisting of five layers (three layers of Mg and two layers of Si) with all Mg–Si fixed bonds, was proposed on the basis of EELS data. The observed redshift of EELS bulk plasmon on 0.8 eV is satisfactorily explained in the framework of the model by the reduction of carrier density and formation of fixed Mg–Si bonds.