Observation of chiral quantum-Hall edge states in graphene

TL;DR

This paper demonstrates a simple conductance measurement method to determine the chirality of quantum-Hall edge states in graphene, revealing their interaction with contacts and aiding understanding of symmetry breaking at high magnetic fields.

Contribution

It introduces a straightforward two-terminal conductance approach to identify the chirality of QH edge states in graphene, especially at zero filling factor.

Findings

Edge state with smaller filling factor interacts more strongly with contacts.

Method effectively determines QH edge state chirality in graphene.

Supports understanding of symmetry breaking in high magnetic fields.

Abstract

In this study, we determined the chiral direction of the quantum-Hall (QH) edge states in graphene by adopting simple two-terminal conductance measurements while grounding different edge positions of the sample. The edge state with a smaller filling factor is found to more strongly interact with the electric contacts. This simple method can be conveniently used to investigate the chirality of the QH edge state with zero filling factor in graphene, which is important to understand the symmetry breaking sequence in high magnetic fields ($\gtrsim$25 T).