SCANNING TUNNELING MICROSCOPY OF MONOLAYER GRAPHITE EPITAXIALLY GROWN ON A TIC(111) SURFACE

The two-dimensional (2D) electronic and atomic structures of monolayer graphite epitaxially grown on a TiC(111) clean surface have been investigated by scanning tunneling microscopy (STM) and low energy electron diffraction (LEED). The atomic structure of the monolayer graphite observed by LEED consists of double superlattices, 2 x 2 and 7 x 7, with respect to the unit meshes of the graphite and the Ti-lattice at the top of the substrate, respectively. These superlattices are rotated 30-degrees with respect to each other. The structure of the monolayer graphite is commensurate with that of the Ti-layer. The electronic structure observed by STM is also modulated by the same superlattices as those of the LEED pattern. The local charge transfer from the Ti-layer to the pi*-bond of the monolayer graphite across the interface has been observed directly by STM with atomic resolution. The surface band structure of the monolayer graphite on TiC(111) is discussed based on the voltage dependence of the constant current image.