Topological charge localization in bilayer graphene induced by an antisymmetric electric potential step

TL;DR

This paper investigates how an antisymmetric electric potential step in bilayer graphene induces topological charge localization, zero-energy modes, and Hall-effect phenomena, with potential applications in information storage and switching devices.

Contribution

It reveals the topological effects of antisymmetric potential steps in bilayer graphene, including zero-energy modes and charge localization, which are novel findings in this context.

Findings

Zero-energy modes emerge when the potential exceeds a threshold.

Kinks acquire charge and induce topological effects.

Hall-effect plateaus resemble those of monolayer graphene.

Abstract

A charged particle whose energy is less than the electric potential step it is incident upon, is expected to undergo partial reflection and transmission. In bilayer graphene, however, a potential step in the form of an antisymmetric kink results in particle localization due to the interaction between the particle and its chiral partner. It is found that when the potential step exceeds a threshold, zero-energy modes of the system emerge, and causes the kink to acquire a charge. The Hall-effect plateaus in the vicinity of the zero modes correspond, unexpectedly, to those of the monolayer. The topological nature of these kink-induced effects and the ease with which a kink can be generated in practice, suggest possible applications in e.g. storage of information or switching devices.