A detailed study of low-temperature magnetoconductance in between quantized
Hall plateaux is presented. The data are obtained for disordered two-termi
nal submicron wires defined in GaAs/AlGaAs heterostructures modulation-dope
d by Si. Slow time evolution of conductance G is observed on the high-field
side of the quantized plateaux - for filling factors v < 3 and v < 2. This
surprising noise is attributed to glassy dynamics of localized electrons i
n the wire centre, and to the corresponding time dependence of the impurity
-assisted tunnelling probability between the current carrying regions. (C)
1998 Elsevier Science B.V. All rights reserved.