The results of the metal-insulator transition （MIT） induced by impurity concentration are presented in the case of metallic and insulating samples 70Ge：Ga p-type. The eight samples studied have Ga concentrations N ...The results of the metal-insulator transition （MIT） induced by impurity concentration are presented in the case of metallic and insulating samples 70Ge：Ga p-type. The eight samples studied have Ga concentrations N ranging from 1.848 × 1017 to 1.912 × 10^17 cm-3. The conductivity measurements were carried out at low temperature in the range 1 to 0.019 K. We provide physical explanations to explain the behaviors of the temperature dependence of the electrical conductivity in both sides of the MIT. The data are for a 70Ge：Ga sample prepared and reported by Itoh et aL in Ref. [Itoh K M, Watanabe M, Ootuka Y, et al. J Phys Soc Jpn, 2004, 73（1）： 173].展开更多
We reanalyzed experimental data already published in Friedman J R, Zhang Y, Dai P, et al. Phys Rev B, 1996, 53（15）： 9528. Variable range hopping （VRH） conduction in the insulating three-dimensional n-CdSe samples...We reanalyzed experimental data already published in Friedman J R, Zhang Y, Dai P, et al. Phys Rev B, 1996, 53（15）： 9528. Variable range hopping （VRH） conduction in the insulating three-dimensional n-CdSe samples has been studied over the entire temperature range from 0.03 to 1 K. In the absence of a magnetic field, the low temperature conductivity a of the three samples （A, B and C） obeys the Mott VRH conduction with an appropriate temperature dependence in the prefactor （a = σ0 exp [- （T0/T）]^p with p ≈ 0.25）. This behavior can be explained by a VRH model where the transport occurs by hopping between localized states in the vicinity of the Fermi level, EF, without creation of the Coulomb gap （CG）. On the contrary, no Efros-Shklovskii VRH is observed, suggesting that the density is constant in the vicinity of the EF.展开更多
文摘The results of the metal-insulator transition （MIT） induced by impurity concentration are presented in the case of metallic and insulating samples 70Ge：Ga p-type. The eight samples studied have Ga concentrations N ranging from 1.848 × 1017 to 1.912 × 10^17 cm-3. The conductivity measurements were carried out at low temperature in the range 1 to 0.019 K. We provide physical explanations to explain the behaviors of the temperature dependence of the electrical conductivity in both sides of the MIT. The data are for a 70Ge：Ga sample prepared and reported by Itoh et aL in Ref. [Itoh K M, Watanabe M, Ootuka Y, et al. J Phys Soc Jpn, 2004, 73（1）： 173].
文摘We reanalyzed experimental data already published in Friedman J R, Zhang Y, Dai P, et al. Phys Rev B, 1996, 53（15）： 9528. Variable range hopping （VRH） conduction in the insulating three-dimensional n-CdSe samples has been studied over the entire temperature range from 0.03 to 1 K. In the absence of a magnetic field, the low temperature conductivity a of the three samples （A, B and C） obeys the Mott VRH conduction with an appropriate temperature dependence in the prefactor （a = σ0 exp [- （T0/T）]^p with p ≈ 0.25）. This behavior can be explained by a VRH model where the transport occurs by hopping between localized states in the vicinity of the Fermi level, EF, without creation of the Coulomb gap （CG）. On the contrary, no Efros-Shklovskii VRH is observed, suggesting that the density is constant in the vicinity of the EF.
