Experimental surface-state band structure of the Ba-induced Si(111) 3X1 surface - art. no. 165312

The surface-state band structure of the Ba-induced single-domain Si(111) 3 x 1 surface was studied in detail via angle-resolved photoelectron spectros copy using synchrotron radiation. Applying different photon energies and ex perimental geometries, we obtained the experimental surface-state band stru cture, including information of the symmetry of the surface states. Our res ults indicate that the surface electronic state is undoubtedly semiconducti ng, in contrast to the prediction of previous band calculations. However, t he dispersion feature of the three nonmetallic surface states is in almost perfect agreement with that calculated for the honeycomb-chained channel mo del. The inconsistency between our results and the theoretical calculation can be explained by the fact that the coverage of alkali-earth metal is not the same as that of alkali metal. Rather, the coverage of alkali-earth met al on the 3 x 1 surface is half that of alkali metal, i.e., 1/6 monolayer.