GOLD-INDUCED RECONSTRUCTIONS OF THE SI(001) SURFACE - THE 5X3 AND ROOT-26X3 PHASES

Scanning tunneling microscopy (STM) and low-energy electron diffraction have been used to study surface reconstructions of Au on the Si(001) surface. A previously reported square-root 26 X 3 superstructure diffraction pattern is shown to correspond to a mixture of 5 X 3 and square-root 26 X 3 phases with the structure of these two phases being closely related. In both structures, the spacing of the surface atoms in the STM images shows a strong uniaxial compression of 17% with respect to the bulk 1 X 1 lattice spacing.