Physical Review B
Using core-level photoemission, a coverage-dependent transition in the adsorption of K on Si(100)2×1 is observed. Below ∼0.25 monolayers, a single adsorption is occupied, the asymmetry of the Si-dimer reconstruction is enhanced, and no more than ∼0.05e is transferred from K to Si. Above this coverage, multiple sites are occupied, the dimer configuration becomes more symmetric, and the K overlayer becomes increasingly metallic. These findings resolve a number of conflicting studies of this system.
"Coverage Dependence of K adsorption on Si(100)—2× 1 by Core-Level Photoemission," D. M. Riffe, G. K. Wertheim, P. H. Citrin, and J. E. Rowe, Phys. Rev. B 45, 3532 (1992).