Change of Surface Electronic States Induced by Li and K Adsorption on the Si(111)7×7 Structure

Abstract
The change of the surface electronic states induced by Li and K adsorption on the Si(111)7×7 surface has been studied using angle-resolved ultraviolet photoelectron spectroscopy. It has been found that with increasing Li coverage, the photoemission intensity of the surface states due to dangling bonds of the 7×7 structure decreases monotonously. However, for K adsorption, the photoemission intensity of the metallic surface state increases at the initial stage. This implies that the 4s electron of a K atom is transferred into the half-filled surface state of the 7×7 structure.