Geometric structure of the Si(111)√3×√3-Ga surface

Abstract

The structure of the Si(111)\ensuremath{\surd}3 \ifmmode\times\else\texttimes\fi{} \ensuremath{\surd}3 -Ga surface has been studied by dynamic analysis of low-energy electron-diffraction curves of intensity versus energy (I-V). It has been found that a structure in which Ga atoms are located on the second layer of Si atoms well explains the experimentally obtained I-V curves. In this geometry, a large deformation of the surface layer results from the stable adsorption of Ga atoms. The optimum configuration is close to that proposed by Northrup in his study of the Si(111)\ensuremath{\surd}3 \ifmmode\times\else\texttimes\fi{} \ensuremath{\surd}3 -Al surface.