Resistance noise scaling in a dilute two-dimensional hole system in GaAs.

We have measured the resistance noise of a two-dimensional (2D) hole system in a high mobility GaAs quantum well, around the 2D metal-insulator transition (MIT) at zero magnetic field. The normalized noise power S R /R 2 increases strongly when the hole density p s is decreased, increases slightly with temperature (T) at the largest densities, and decreases strongly with T at low p s . The noise scales with the resistance, S R /R 2 ∼ R 2 , 4 , as for a second order phase transition such as a percolation transition. The p s dependence of the conductivity is consistent with a critical behavior for such a transition, near a density p* which is lower than the observed MIT critical density p c .