Ballistic magnetotransport in graphene

TL;DR

This paper investigates how a perpendicular magnetic field affects the conductivity of doped graphene in the ballistic regime, revealing an anomalous correction and a characteristic temperature dependence of magnetoresistance.

Contribution

It introduces a novel understanding of magnetic field effects on ballistic graphene, highlighting the role of chiral symmetry breaking and impurity nature in magnetotransport behavior.

Findings

Magnetoresistance scales inversely with temperature, δρₓₓ(T) ∝ 1/T.

Anomalous interaction correction to conductivity due to magnetic field.

Proposes experiments to identify impurity types in high-mobility Dirac materials.

Abstract

We report that a perpendicular magnetic field introduces an anomalous interaction correction, $\delta \sigma$, to the static conductivity of doped graphene in the ballistic regime. The correction implies that the magnetoresistance, $\delta \rho_{xx}$ scales inversely with temperature $\delta \rho_{xx}(T) \propto 1/T$ in a parametrically large interval. When the disorder is scalar-like, the $\propto 1/T$ behavior is the leading contribution in the crossover between diffusive regime exhibiting weak localization and quantum magnetooscillations. The behavior originates from the field-induced breaking of the chiral symmetry of Dirac electrons around a single valley. The result is specific for generic two-dimensional Dirac materials which deviate from the half-filling. We conclude by proposing magnetotransport experiments, which have the capacity to detect the nature of impurities and defects in high-mobility Dirac monolayers such as recently fabricated ballistic graphene samples.