IUVSTA 15th International Vacuum Congress (IVC-15), AVS 48th International Symposium (AVS-48), 11th International Conference on Solid Surfaces (ICSS-11)
    Surface Science Thursday Sessions
       Session SS2-ThM

Paper SS2-ThM9
Electronic Structure of the Alkali Halide-metal Interfaces: LiCl(100)/ Cu(100)

Thursday, November 1, 2001, 11:00 am, Room 122

Session: Electronic Structure II
Presenter: M. Kiguchi, The University of Tokyo, Japan
Authors: M. Kiguchi, The University of Tokyo, Japan
H. Inoue, The University of Tokyo, Japan
K. Saiki, The University of Tokyo, Japan
A. Koma, The University of Tokyo, Japan
Correspondent: Click to Email
When an insulator film is prepared in the close vicinity of a metal surface, a novel phase is formed whose property may differ from the bulk one. It is suggested that the band gap is reduced for an insulating thin film on a metal substrate, due to the presence of the dielectric boundary and the overlayer reduced dimensionally. However, the large difference of chemical bond between metals and insulators makes it difficult to form a well ordered interface. The electronic structure of the insulator-metal interface has been little studied. Recently, we have succeeded in growing a single-crystalline LiCl film on Cu(100) in a layer-by-layer fashion. In the present work, we have studied the electronic structure of LiCl film on Cu(100) using EELS (electron energy loss spectroscopy) and UPS (ultraviolet photoelectron spectroscopy), as a model system of alkali halide-metal interface. The EEL spectrum(Ep=60 eV) shows clear band gap region from 0 eV to 7 eV. The band gap energy did not change for the LiCl thickness from 1 ML to 20 ML. In addition, the 61 eV loss peak observed in the EELS (Ep=200eV) did not change with the thickness. The result of EELS indicates that relative position of the conduction band to the valence band and to the Li 1s core band was unchanged. In the result of UPS, on the other hand, the valence band showed upward shift with decreasing film thickness. The results of EELS and UPS suggest the occurrence of the bend bending in ionic layers.