Scattering of topological kink-antikink states in bilayer graphene structures

TL;DR

This paper investigates how kink-antikink potentials in bilayer graphene influence topological electron states, revealing novel scattering behaviors, conductance features, and valley filtering capabilities relevant for valleytronics.

Contribution

It demonstrates how kink-antikink interactions modulate topological currents and produce conductance anomalies, advancing understanding of topological states in bilayer graphene.

Findings

Kink-antikink coupling causes anomalous conductance steps.

System energy spectrum can be extracted from conductance when a loop forms.

Devices can function as valley filters with small magnetic fields.

Abstract

Gapped bilayer graphene can support the presence of intragap states due to kink gate potentials applied to the graphene layers. Electrons in these states display valley-momentum locking, which makes them attractive for topological valleytronics. Here, we show that kink-antikink local potentials enable modulated scattering of topological currents. We find that the kink-antikink coupling leads to anomalous steps in the junction conductance. Further, when the constriction detaches from the propagating modes, forming a loop, the conductance reveals the system energy spectrum. Remarkably, these kink-antikink devices can also work as valley filters with tiny magnetic fields by tuning a central gate.