We measured on the dielectric side, with |N/Nc - 1| ≤ 0.64 the critical indices of the metal-insulator transition (MIT) in n-Ge with low (1.4 and 12%) and medium (38 and 54%) compensation, prepared by neutron-transmutation doping (NTD) of isotopic mixtures of 74Ge and 70Ge. We analyzed from the temperature dependence of hopping resistance in the variable-range hopping (VRH) regime with Coulomb gap the scaling of the localization length a, and of the dielectric constant N. At low compensation we find that the critical indices are ν ≈ 1/2, ζ ≈ 1, which increase up to ν ≈ 1, ζ ≈ 2, for medium compensations.
|Number of pages||5|
|Journal||Physica Status Solidi (B): Basic Research|
|State||Published - Jan 1998|