2004 Volume 2 Pages 191-199
A series of our studies are reviewed on the atomic and electronic structures at well-defined alkali halide/metal interfaces. Alkali halides are found to grow heteroepitaxially on fcc metal (001) surfaces, that is, a well-defined insulator/metal interface can be prepared. The electronic structure at the interface is studied by near edge x-ray absorption fine structure (NEXAFS), x-ray photoemission spectroscopy and Auger electron spectroscopy. We can show a clear experimental evidence for the formation of metal induced gap states (MIGS), which originate not from chemical bonds at the interface, but from states formed by the proximity to a metal. The character of MIGS is studied by the polarization and thickness dependent NEXAFS. MIGS are states whose wave functions orient in the surface normal direction. The decay length of MIGS is about mono layer thickness, and it depends on rather an alkali halide than a metal. Finally, we discuss a possibility of the interface superconductivity. [DOI:10.1380/ejssnt.2004.191]
