SCALING BEHAVIOR OF THE ACTIVATED CONDUCTIVITY IN A QUANTUM HALL LIQUID

We propose a scaling model for the universal longitudinal conductivity near the mobility edge for the integer quantum Hall liquid. We fit ou r model with available experimental data on exponentially activated co nductance near the Landau-level tails in the integer quantum Hall regi me. We obtain quantitative agreement between our scaling model and the experimental data over a wide temperature and magnetic field range.