Gated GaAs/AlxGaAs1−x heterostructures were used to determine the low temperature behavior of the two-dimensional electron gas near filling factor ν = 1 in the disorder-magnetic field plane. We identify a line on which 2 σxy is temperature independent, has value σxy = 0.5±0.02 (e2/h), and a distinct line on which ρxy = 2±0.04 (h/e2). The phase boundaries between the Hall insulator and the principal quantum Hall liquids at ν = 1 and 1 3 show levitation of the delocalized states of the first Landau level for electrons and composite fermions. Finally, data suggests that there is no true metallic phase around ν =
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