Metal-Semiconductor Fluctuation In The Sn Adatoms In The Si(111)-Sn And Ge(111)-Sn (Root-3x-Root-3)R30-Degrees Reconstructions

The two components of the Sn 4d core level in the Si(111)-Sn and Ge(111)-Sn. (root 3 X root 3)R30 degrees structures are proposed to arise from semiconductor-metal fluctuations in the Sn adatom layer. Adsorption of potassium on the Si(111)-Sn (root 3 X root 3)R30 degrees surface suppresses the metallic component and shifts the tin into a purely semiconducting phase with a filled dangling bond state.