Electron Transport in Low-Stage Graphite-ICl Intercalation Compounds

The in-plane electron transport properties of stages-1 and -2 intercalation compounds of graphite with iodine-monochrolide (ICl) have been investigated between room and liquid helium temperatures. The characteristic T 2 term appearing in the temperature dependence of their resistivities is pointed out to originate from the discal equi-energy surface of out-of-plane mode phonons intersecting the long cylindrical Fermi surface, while the carrier scattering by in-plane longitudinal mode phonons showing a too steep dispersion diagram is neglegibly small. These compounds can be approximated to simple two-dimensional hole metals in the description of most transport effects. However, the appreciable magnetoresistance is observed even for the stage-1 which has just one band; this implies that the Fermi surface is trigonally warped so as to provide single anisotropic carriers in the basal plane.