A study on the universality of the magnetic-field-induced phase transitions in the two-dimensional electron system in an AlGaAs/GaAs heterostructure

Plateau–plateau (P–P) and insulator–quantum Hall conductor (I–QH) transitions are observed in the two-dimensional electron system in an AlGaAs/GaAs heterostructure. At high fields, the critical conductivities are not of the expected universal values and the temperature-dependence of the width of the P–P transition does not follow the universal scaling. However, the semicircle law still holds, and universal scaling behavior was found in the P–P transition after mapping it to the I–QH transition by the Landau-level addition transformation. We pointed out that in order to get a correct critical exponent, it is essential that the scaling analysis must be performed near the critical point. And with proper analysis, we found that the P–P transition and the insulator quantum Hall conductor are of the same universal class.