MONOLAYER GRAPHITE ON TAC(111) - ELECTRONIC BAND-STRUCTURE

The electronic band structure of the monolayer graphite/TaC(111) syste m was examined using XPS, AES, and ARUPS and the results were compared with predictions of the rigid-band model to determine its validity. T he measured graphite sigma1 band energy relative to the Fermi energy i s -23.0 eV at GAMMABAR and the pi1 band energy is -10.3 eV at GAMMABAR and -3.4 eV at KBAR. By comparing these values to the results of a li nearized augmented-plane-wave calculation of the electronic structure of an isolated graphite monolayer, the qualitative picture of charge t ransfer from the substrate into the graphite overlayer is confirmed, b ut the rigid-band model is not sufficient to explain the observed bind ing energy differences between experiment and theory. The degree of hy bridization between the electronic bands of TaC and the graphite monol ayer is therefore not negligible and should be included in description s of the electronic band structures of such systems.