  The 1/f resistance noise of a two-dimensional (2D) hole system in a high
mobility GaAs quantum well has been measured on both sides of the 2D
metal-insulator transition (MIT) at zero magnetic field (B=0), and deep in the
insulating regime. The two measurement methods used are described: I or V
fixed, and measurement of resp. V or I fluctuations. The normalized noise
magnitude SR/R^2 increases strongly when the hole density is decreased, and its
temperature (T) dependence goes from a slight increase with T at the largest
densities, to a strong decrease at low density. We find that the noise
magnitude scales with the resistance, SR /R^2 ~ R^2.4. Such a scaling is
expected for a second order phase transition or a percolation transition. The
possible presence of such a transition is investigated by studying the
dependence of the conductivity as a function of the density. This dependence is
consistent with a critical behavior close to a critical density p* lower than
the usual MIT critical density pc.

Strongly Correlated Electrons;Disordered Systems and Neural Networks