Twisted nanoporous graphene/graphene bilayers: electronic decoupling and chiral currents

TL;DR

This study explores how twisting bilayer nanoporous graphene and related materials affects their electronic coupling and current flow, revealing twist-dependent phenomena like chiral currents and resonant states.

Contribution

It provides a detailed atomistic analysis of twist-angle effects on electronic properties and introduces the concept of twist-induced chiral currents in nanoporous graphene bilayers.

Findings

Strong coupling and hybridization at small twist angles

Emergence of chiral currents due to symmetry breaking

Resonant peaks in density of states at small angles

Abstract

We investigate bilayers of nanoporous graphene (NPG), laterally bonded carbon nanoribbons, and graphene. The electronic and transport properties are explored as a function of the interlayer twist angle using an atomistic tight-binding model combined with non-equilibrium Green's functions. At small twist angles ($\theta \lesssim 10^\circ$), NPG and graphene are strongly coupled, as revealed by the hybridization of their electronic bands. As a result, when electrons are point-injected in NPG, a substantial interlayer transmission occurs and an electronic Talbot-like interference pattern appears in the current flow on both layers. Besides, the twist-induced mirror-symmetry-breaking leads to chiral features in the injected current. Upon increasing the twist angle, the coupling is weakened and the monolayer electronic properties are restored. Furthermore, we demonstrate the emergence of resonant peaks in the electronic density of states for small twist angles, allowing to probe the twist-dependent interlayer coupling via scanning tunneling microscopy.