De Haas-van Alphen effect in pyrolytic and single crystal graphite

Abstract

De Haas-van Alphen oscillations have been observed in the differential susceptibility of well-annealed pyrolytic graphite (PG) with the low frequency field modulation technique. The results for PG are compared with similar studies of natural single crystal (SCG) by Soule et al., and by the present authors. This provides a detailed comparison of the Fermi surface and certain features of band structure in PG and SCG. Observation of a long period, minority carrier DHVA oscillation in PG and SCG in addition to the majority electron and hole DHVA osculations confirms Soule's discovery of such a minority carrier oscillation in SCG and provides a sensitive test for the Slonczewski-Weiss band model. The long period oscillation is attributed to magnet energy levels passing through the Fermi level near the Brillouin zone corner at k z = π/ co. This interpretation is supported by the excellent agreement for PG between the predicted values and experimental results for the period, effective mass, period anisotropy, and phase. A similar analysis for SCG was not as successful, indicating that certain band parameters and the magnitude of the spin-orbit coupling in SCG may differ from similar parameters in PG. The existence of minority carrier oscillations in PG indicates that the hole and electron Fermi surfaces are closed and that the electron surface intersects the hexagonal face of the Brillouin zone.