Puddle-induced resistance oscillations in the breakdown of the graphene quantum Hall effect

TL;DR

This study investigates the stability and breakdown phenomena of the quantum Hall effect in wide graphene Hall bars, revealing resistance oscillations linked to electron reservoirs and inhomogeneities that influence plateau stability.

Contribution

It uncovers the role of electron reservoirs and inhomogeneities in modulating the quantum Hall effect breakdown in graphene, with detailed high-field experimental analysis.

Findings

Quantum Hall plateau persists from 5 T to 80 T.

Resistance oscillations with 1/B periodicity observed during breakdown.

In-plane inhomogeneities decrease breakdown current and affect plateau stability.

Abstract

We report on the stability of the quantum Hall plateau in wide Hall bars made from a chemically gated graphene film grown on SiC. The $\nu=2$ quantized plateau appears from fields $B \simeq 5$ T and persists up to $B \simeq 80$ T. At high current density, in the breakdown regime, the longitudinal resistance oscillates with a $1/B$ periodicity and an anomalous phase, which we relate to the presence of additional electron reservoirs. The high field experimental data suggest that these reservoirs induce a continuous increase of the carrier density up to the highest available magnetic field, thus enlarging the quantum plateaus. These in-plane inhomogeneities, in the form of high carrier density graphene pockets, modulate the quantum Hall effect breakdown and decrease the breakdown current.