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

TL;DR

This study investigates the universality of magnetic-field-induced phase transitions in a 2D electron system within AlGaAs/GaAs heterostructures, revealing that different transitions belong to the same universal class when proper scaling analysis is applied.

Contribution

It demonstrates that plateau-plateau and insulator-quantum Hall transitions are of the same universal class with correct scaling analysis, despite deviations at high fields.

Findings

Universal scaling behavior observed after Landau-level transformation

Critical conductivities deviate from expected universal values at high fields

Proper scaling analysis near the critical point is essential for accurate critical exponents

Abstract

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 transitions are of the same universal class.