Electrical manipulation of the edge states in graphene and the effect on the quantum Hall transport

TL;DR

This study explores how applying an in-plane electric bias to graphene under a magnetic field creates shortcut edge states that alter quantum Hall transport, leading to unconventional Hall plateaus and novel resistance behaviors.

Contribution

It reveals the emergence of shortcut edge states induced by electric bias in graphene and their impact on quantum Hall transport, a novel phenomenon not previously documented.

Findings

Shortcut edge states appear under electric bias in graphene.

New quantum Hall plateaus are observed due to these states.

Shortcut states influence transverse and longitudinal resistance.

Abstract

We investigate new properties of the Dirac electrons in the finite graphene sample under perpendicular magnetic field that emerge when an in-plane electric bias is also applied. The numerical analysis of the Hofstadter spectrum and of the edge-type wave functions evidentiate the presence of shortcut edge states that appear under the influence of the electric field. The states are characterized by a specific spatial distribution, which follows only partially the perimeter, and exhibit ridges that shortcut opposite sides of the graphene plaquette. Two kinds of such states have been found in different regions of the spectrum, their particular spatial localization being shown along with the diamagnetic moments that reveal their chirality. By simulating a four-lead Hall device, we investigate the transport properties and observe new, unconventional plateaus of the integer quantum Hall effect, which are associated with the presence of the shortcut edge states. The contributions of the novel states to the transmittance matrix that determine the new transport properties are shown. The shortcut edge states resulting from the splitting of the n=0 Landau level represent a special case, giving rise to non-trivial transverse and longitudinal resistance.