Weak non-Landau-type contributions to the diamagnetism of graphite

Abstract

The exceptionally large diamagnetic susceptibility of a single-crystal graphite in the direction perpendicular to the graphene layers is caused by the Landau levels. However, there are also other contributions to the magnetic susceptibility. In particular, in metals the Pauli paramagnetism is leading, whereas in dielectrics the diamagnetic Langevin and paramagnetic Van Vleck terms are essential. These components of magnetic susceptibility are also present in graphite. In this work, we calculate the magnitudes of all these small contributions from first principles. It is found that the Pauli paramagnetism is negligible (2.3 x 10^{-9} emu/g), whereas the other diamagnetic contribution - arising from the Langevin and Van Vleck mechanisms - is comparable to the in-plane experimental diamagnetism of graphite and to the diamagnetic response of C60 and C70} fullerenes. This diamagnetic contribution proves to be slightly anisotropic (-2.93 x 10^{-7} emu/g along the x- or y-axes and -2.24 x 10^{-7} emu/g along the $z-$axis), with the averaged value -2.7 x 10^{-7} emu/g.