THE QUANTUM CORRECTIONS TO THE CONDUCTIVITY FOR HOMOGENEOUSLY DOPED BARELY METALLIC GERMANIUM

We report the results of electrical conductivity studies down to 30 mK for barely metallic samples in the vicinity of the metal-insulator tr ansition (MIT). We used isotopically enriched Ge-74 crystals and neutr on-transmutation doping to produce homogeneously doped n-type germaniu m with As donors and with compensation degree of about 12%. We found t hat the temperature dependence of the conductivity obeys a logarithmic -like behavior within the experimental range of temperatures. This imp lies the existence of another mechanism for the scattering apart from the electron-electron interaction. According to the theory of Fukuyama tile In(T) dependence should be due to some kind of magnetic scatteri ng. Therefore, it is impossible to obtain the scaling behavior of the conductivity at zero temperature as a function of the impurity concent ration in tie vicinity of the MIT due to the divergence of In (T) at T --> 0.