Oscillatory variations of the diagonal (Gxx) and Hall (Gxy)
magnetoconductances are discussed in view of topological scaling effects giving
rise to the quantum Hall effect. They occur in a field range without
oscillations of the density of states due to Landau quantization, and are,
therefore, totally different from the Shubnikov-de Haas oscillations. Such
oscillations are experimentally observed in disordered GaAs layers in the
extreme quantum limit of applied magnetic field with a good description by the
unified scaling theory of the integer and fractional quantum Hall effect.Comment: 4 pages, 4 figure