3-DIMENSIONAL ENERGY-BAND IN STAGE-1 ACCEPTOR GRAPHITE-INTERCALATION COMPOUNDS

low-frequency de Haas-van Alphen (dHvA) oscillation of the stage-1 CdC l2 graphite intercalation compound (GIG) and of the SbF6- compound was investigated as a function of magnetic-field direction theta with res pect to the c axis. For the angular range of measurement of 0 < theta < 20 degrees the frequency was independent of theta within experimenta l uncertainty in both compounds and did not follow the relation f(thet a) = f(0)sec theta for a cylindrical Fermi surface. For the angular ra nge of measurement, the extremal cross-sectional areas of the Fermi su rface for the low-frequency are that of a sphere. This indicates a sig nificant three-dimensional component of the graphitic energy band for the low frequency.