Pseudo-diffusive magnetotransport in graphene

TL;DR

This paper investigates the transport properties of ballistic graphene junctions under various dopings and magnetic fields, revealing a fragile pseudo-diffusive regime at the Dirac point and its crossover to other transport regimes.

Contribution

It uncovers the conditions under which pseudo-diffusive transport occurs and how it transitions to other regimes in graphene under magnetic fields and doping.

Findings

Pseudo-diffusive transport is independent of magnetic field at the Dirac point.

Fragility of pseudo-diffusive regime with respect to doping at finite magnetic fields.

Recovery of pseudo-diffusive transport near Landau level resonances at high magnetic fields.

Abstract

Transport properties through wide and short ballistic graphene junctions are studied in the presence of arbitrary dopings and magnetic fields. No dependence on the magnetic field is observed at the Dirac point for any current cumulant, just as in a classical diffusive system, both in normal-graphene-normal and normal-graphene-superconductor junctions. This pseudo-diffusive regime is however extremely fragile respect to doping at finite fields. We identify the crossovers to a field-suppressed and a normal ballistic transport regime in the magnetic field - doping parameter space, and provide a physical interpretation of the phase diagram. Remarkably, pseudo-diffusive transport is recovered away from the Dirac point in resonance with Landau levels at high magnetic fields.