Nonuniversal Scaling Behavior of Conductivity Peak Widths in the Quantum Hall Effect in InGaAs/InAlAs Structures

The longitudinal ρ xx and Hall ρ xy resistances were measured in the region of the quantum phase transitions for the quantum Hall effect regime with magnetic fields up to 12 T at temperatures of T = 0.4–30 K in two-dimensional electron systems n -In 0.9 Ga 0.1 As/In 0.81 Al 0.19 As. The nonuniversal scaling behavior of the temperature dependence of the width of the resistance ρ xx peaks related to the effect of the large-scale random potential and of Landau-level mixing with opposite spin directions was found.