Fractional Quantum Hall plateaus in mosaic-like conductors

TL;DR

This paper presents a simple model and experimental evidence showing that fractional quantum Hall conductance plateaus can arise from mosaic-like conductors with integer quantum Hall tiles and metallic links, without requiring interaction-driven physics.

Contribution

The study introduces a minimal model explaining fractional quantum Hall-like conductance in mosaic conductors and supports it with graphene mosaic experiments, challenging the traditional interaction-based interpretation.

Findings

Fractional conductance plateaus can emerge from mosaic structures.

Richer fractional spectra occur with parameter variation.

Experimental graphene mosaics exhibit similar fractional features.

Abstract

We report a simple route to generate magnetotransport data that results in fractional quantum Hall plateaus in the conductance. Ingredients to the generating model are conducting tiles with integer quantum Hall effect and metallic linkers, further Kirchhoff rules. When connecting few identical tiles in a mosaic, fractional steps occur in the conductance values. Richer spectra representing several fractions occur when the tiles are parametrically varied. Parts of the simulation data are supported with purposefully designed graphene mosaics in high magnetic fields. The findings emphasize that the occurrence of fractional conductance values, in particular in two-terminal measurements, does not necessarily indicate interaction-driven physics. We underscore the importance of an independent determination of charge densities and critically discuss similarities with and differences to the fractional quantum Hall effect.