Dissipative Quantum Hall Effect in Graphene near the Dirac Point

TL;DR

This paper investigates the unique dissipative quantum Hall effect at nu=0 in graphene, revealing counter-propagating edge states that lead to unusual resistivity behavior and challenge existing theoretical models.

Contribution

It demonstrates the presence of gapless edge states in the nu=0 quantum Hall regime in graphene, providing new insights into its electronic transport properties.

Findings

Large longitudinal resistivity rho_xx > h/e^2 at nu=0

Pronounced fluctuations in rho_xy and rho_xx observed

Smeared zero Hall plateau consistent with experiments

Abstract

We report on the unusual nature of nu=0 state in the integer quantum Hall effect (QHE) in graphene and show that electron transport in this regime is dominated by counter-propagating edge states. Such states, intrinsic to massless Dirac quasiparticles, manifest themselves in a large longitudinal resistivity rho_xx > h/e^2, in striking contrast to rho_xx behavior in the standard QHE. The nu=0 state in graphene is also predicted to exhibit pronounced fluctuations in rho_xy and rho_xx and a smeared zero Hall plateau in sigma_xy, in agreement with experiment. The existence of gapless edge states puts stringent constraints on possible theoretical models of the nu=0 state.