Dirac and Normal Fermions in Graphite and Graphene: Implications to the Quantum Hall Effect

Spectral analysis of Shubnikov de Haas (SdH) oscillations of magnetoresistance and of Quantum Hall Effect (QHE) measured in quasi-2D highly oriented pyrolytic graphite (HOPG) reveals two types of carriers: normal (massive) electrons with Berry phase $0$ and Dirac-like (massless) holes with Berry phase $\pi$. We demonstrate that recently reported integer- and semi-integer QHE for bi-layer and single-layer graphenes take place simultaneously in HOPG samples.