Pb thin films on Si(111): Local density of states and defects

Local density of states and atomic structure of the stripped incommensurate phase, the √3 ×√7 phase and the 1 × 1 phase of a monolayer of Pb on Si(111) are characterized by scanning tunneling microscopy and spectroscopy. The dI/dV-images reveal congruent local density of states structures for the stripped incommensurate and the √3 ×√ phase but suggest a hexagonal lattice of the local density of states for the 1×1 phase while the atomic structure consists of one more atom in the center of each hexagon. Vacancy defects and impurities show a depletion of local density of states for the stripped incommensurate and √3 ×√7 phase. Vacancies and impurities show an increase and no clear depletion in local density of states for the 1 × 1 phase, respectively.