Transport in Graphene p-n Junctions in Magnetic Field

TL;DR

This paper investigates ballistic transport in graphene p-n junctions under magnetic fields, revealing regimes of partial suppression and complete pinching off, and introduces a field-tunable current switch based on collimation angle control.

Contribution

It presents a novel theoretical approach to analyze transmission in graphene p-n junctions under magnetic fields, including bilayer graphene, highlighting the persistence of chiral dynamics.

Findings

Perfect transmission at a field-dependent collimation angle.

Transport suppression at low magnetic fields.

Landau level formation pinches off the junction at high fields.

Abstract

Ballistic transport in graphene p-n junctions in the presence of magnetic field exhibits two distinct regimes: At low fields, transport is partially suppressed by the field. When the field exceeds a certain critical value, the junction is pinched off by the Landau level formation. Transmission and conductance are found in the entire range of fields using Lorentz boost and mapping to the Landau-Zener problem. We show that perfect transmission occurs at a field-dependent collimation angle, indicating that the chiral dynamics of massless Dirac fermions persists at a finite magnetic field. A current switch, utilizing field-tunable collimation angle, is proposed. With a generalization of the developed approach we study transmission through p-n junctions in graphene bilayer.