Temperature Dependence and Anisotropy of Resistivity of Graphite in High Temperatures

Abstract

The phonon limited resistivities ρ a and ρ c in directions of a - and c -axes have been calculated with use of the variational formula. In high temperatures, both the inelastic and inter-band scatterings become dominant, in addition to the usual acoustic phonon scattering. The phonon mode is approximated as a layered mode localized on a layer. Both ρ a and ρ c increase with the increase of temperature, but the ratio of resistivity, ρ c /ρ a , decreases monotonically and approaches to the anisotropy ratio of the effective mass in higher temperatures. The observed a -axis resistivity on a pyrolytic graphite agrees with the present calculation, but there is large discrepancy for the c -axis. The effect of the stacking fault is estimated, but very high density is required for the explanation of the observed magnitude of ρ c .