From semiclassical transport to quantum Hall effect under low-field Landau quantization

TL;DR

This paper investigates the transition from semiclassical transport to the quantum Hall effect in a 2D electron system, highlighting the extended validity of the SdH theory and the importance of positive magnetoresistance.

Contribution

It demonstrates that the semiclassical SdH theory remains valid near quantum Hall regimes and emphasizes the role of disorder, temperature, and positive magnetoresistance in this extension.

Findings

SdH theory valid near zero longitudinal resistivity minima

Plateau-plateau transition-like behavior observed

Positive magnetoresistance is crucial for accurate modeling

Abstract

The crossover from the semiclassical transport to quantum Hall effect is studied by examining a two-dimensional electron system in an AlGaAs/GaAs heterostructure. By probing the magneto-oscillations, it is shown that the semiclassical Shubnikov-de Haas (SdH) formulation can be valid even when the minima of the longitudinal resistivity approach zero. The extension of the applicable range of the SdH theory could be due to the damping effects resulting from disorder and temperature. Moreover, we observed plateau-plateau transition like behavior with such an extension. From our study, it is important to include the positive magnetoresistance to refine the SdH theory.