A. Arndt, D. Spoddig, P. Esquinazi, J. Barzola-Quiquia, S. Dusari, and T. Butz

We investigate the dependence of the electrical resistivity and magnetoresistance of single crystalline micrometer-sized graphite samples of a few tens of nanometers thick on the defect concentration produced by irradiation at low fluences. We show that the carrier density of graphite n is extremely sensitive to the induced defects for concentrations as low as ∼0.1 ppm and followsn∼1/R_V² with R_V the distance between defects in the graphene plane. These and Shubnikov-de Haas oscillations results indicate that at least a relevant part of the carrier densities measured in graphite is not intrinsic.