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We have investigated the electrical transport properties of the insulating three-dimensional samples 70Ge: Ga p-type in the temperature range 0.05-2.7 K and in the absence of the magnetic field. The fourteen samples studied have Ga concentrations N ranging from 0.302 × 1017 to 1.84 × 1017 cm-3. On the insulating side of the transition, the study of the effect of low Temperature T on the electrical transport shown that the temperature dependence of the electrical conductivity is found to follow the Efros-Shklovskii Variable Range Hopping regime (ES VRH) with T-1/2 over the whole temperature range.This behaviour assumes that the carriers’ interactions reduces the Density Of State of carriers (DOS) in the vicinity of the Fermi leve and creates the Coulomb gap (CG).The data are for a 70Ge:Ga sample prepared and reported by Itoh et al. in Ref.[ K. M. Itoh, E. E. Haller, J. W. Beeman, W. L. Hansen, et al. Phys. Rev. Lett 77, 4058 (1996)] .