The effect of carrier density gradients on magnetotransport data measured in Hall bar geometry

TL;DR

This paper investigates how small carrier density gradients affect magnetotransport measurements in Hall bar geometries, revealing resistance asymmetries that impact analysis of quantum Hall effects.

Contribution

It provides a simple explanation for resistance interchange phenomena caused by density gradients and discusses implications for quantum Hall conductivity analysis.

Findings

Resistance at both sides of the Hall bar interchange when reversing magnetic field polarity.

Carrier density gradients cause measurable asymmetries in magnetotransport data.

Implications for accurately extracting conductivity flow diagrams in quantum Hall studies.

Abstract

We have measured magnetotransport of the two-dimensional electron gas in a Hall bar geometry in the presence of small carrier density gradients. We find that the longitudinal resistances measured at both sides of the Hall bar interchange by reversing the polarity of the magnetic field. We offer a simple explanation for this effect and discuss implications for extracting conductivity flow diagrams of the integer quantum Hall effect.