ELECTRON-ENERGY BANDS IN SINGLE-CRYSTALLINE LA-INTERCALATED GRAPHITE

A graphite-intercalation compound (GIG) of La was prepared by a therma lly induced surface reaction of a metallic La film on a graphite (0001 ) substrate. The LEED pattern shows a characteristic (root 3 x root 3) R30 degrees reconstruction pointing to the formation of LaC6. Angle-r esolved photoemission combined with Fermi-surfaces mapping reveals a s trongly anisotropic electronic bandstructure of La-GIC. The unfolded p i-symmetry graphite-derived bands in the La intercalation compound may be described in good approximation within a simple rigid-band model b y charge transfer from La to graphite. Despite the presence of filled La-5d states large photoemission intensities close to the Fermi level around the K-points of the nonreconstructed Brillouin zone are related to carbon-derived p(pi)-bands, which become partly occupied in the G IC.