STRUCTURE OF THE K ADSORBED SI(001)2X1 SURFACE STUDIED BY LEED

The surface structures of K adsorbed Si(001))2 x 1 surfaces have been studied by the dynamical analysis of low-energy electron diffraction (LEED) beam intensity versus electron energy curves (the so-called I-V curves). A reliability factor (R-factor) analysis has been carried out for three models of the site of the K atoms, that is, a pedestal site model (Levine's model), a double layer model, and a cave site model. Although the difference of the numerical value of R is not so large among these models, the double layer model indicates the smallest value within a symmetric dimer model of the topmost Si atoms.