Gate-controlled conductance enhancement from quantum Hall channels along graphene p-n junctions

TL;DR

This paper investigates how gate-controlled quantum Hall channels form within graphene p-n junctions, leading to conductance enhancement and potential for probing quantum Hall channel interactions away from edges.

Contribution

It demonstrates the formation of bulk quantum Hall channels in graphene p-n junctions controlled by gating, revealing new conductance pathways and interaction possibilities.

Findings

Enhanced conductance in bipolar doping regimes

Quantum Hall channels form in the bulk of graphene

Gate control determines channel properties and coupling

Abstract

The formation of quantum Hall channels inside the bulk of graphene is studied using various contact and gate geometries. p-n junctions are created along the longitudinal direction of samples, and enhanced conductance is observed in the case of bipolar doping due to new conducting channels forming in the bulk, whose position, propagating direction and, in one geometry, coupling to electrodes are determined by the gate-controlled filling factor across the device. This effect could be exploited to probe the behavior and interaction of quantum Hall channels protected against uncontrolled scattering at the edges.