A FIRST-PRINCIPLES STUDY OF LI-METAL ADSORPTION ON A SI(100) SURFACE

Abstract

We present the results of self-consistent ab initio pseudopotential calculations for the equilibrium structure of Li adsorbed Si(100) surfaces. The stable adsorption sites ale determined for a wide range of Li coverage (Theta=1/2-2). At half-monolayer coverage, the 2x2 structure with Li atoms occupied at the interdimer bridge sites is found to be most stable, while at one-monolayer coverage Li atoms are adsorbed at both the pedestal and cave sites, exhibiting a 2x1 structure where the Si dimers are symmetric. At Theta=2, we find the most stable phase to be the 1x1 structure, which is formed by breaking all the Si dimers of the substrate. From the calculated formation energies, we suggest that the saturation coverage is Theta=2.