FePc/Metal Interfaces Driven by the Electronic States of Different Low-Dimensional Ag Structures Formed on Si(111)

The characteristic electronic structure of low-dimensional Ag structures on semiconductor, i.e., Si(111)-?3 × ?3-Ag superstructure and Ag quantum well state (QWS), were used to explore the interaction between two-dimensional electron gas and a metal-organic molecule, Fe-phthalocyanine (FePc), using angle-resolved photoelectron and X-ray absorption (XAS) spectroscopies. The characteristic surface states of the Ag low-dimensional (LD) system close to the Fermi level (EF), produced either by an excess of Ag atoms on the Si(111)-?3 × ?3-Ag superstructure or by confinement near the surface as in Ag-QWS, are actively involved in the charge reorganization at the FePc/Ag(LD) interfaces. In the first case, the surface state S1 undergoes a change in its binding energy (BE) and an increase in its electron population; in the latter, the diameter of the Fermi map of the surface state (SS) decreases by 50% suggesting the reduction of its electron population. The two FePc/Ag(LD) systems manifest interface states located at dissimilar BE and with different FePc orbital character as established by photon- and polarization-dependent photoemission measurements. (Figure Presented).