Nature of current flow in the regime of the quantum Hall effect

TL;DR

This paper investigates the current flow in the quantum Hall effect regime, confirming chiral flow during quantized plateaus and homogeneous flow elsewhere, enhancing understanding for quantum technology applications.

Contribution

It provides experimental evidence clarifying current distribution in the quantum Hall regime, resolving long-standing disputes and validating models for different regimes.

Findings

Current flow is chiral during quantized Hall plateaus.

Between plateaus, current flow follows the Drude model.

Experimental data supports theoretical models of current distribution.

Abstract

The integer quantum Hall effect (QHE) belongs to the most fundamental phenomena of solid state physics and has an important application as resistance standard. It serves as a basis to understand the fractional, anomalous or spin QHEs, candidates for applications in quantum technology due to their topological properties. For optimizing all these applications it is essential to understand where the current flows inside the Hall bar, a question disputed for decades. We perform multiterminal current measurements on a Hall bar and compare the results with limiting models. We confirm, based on these experiments, that the current flow is chiral for the plateaus of quantized Hall resistance. Everywhere else, including the ranges between plateaus, our results comply with the Drude model, which predicts homogeneous current flow across a homogeneous Hall-bar.