Twisting nanoporous graphene on graphene: electronic decoupling and chiral currents

Abstract

Nanoporous graphene (NPG), laterally bonded carbon nanoribbons, is a promising platform for controlling coherent electron propagation in the nanoscale. However, for its successful device integration NPG should ideally be on a substrate that preserves or enhances its anisotropic transport properties. Here, using an atomistic tight-binding model combined with nonequilibrium Green’s functions, we study NPG on graphene and show that their electronic coupling is modulated as a function of the interlayer twist angle. At small twist angles (θ ≲ 10°), strong hybridization leads to substantial interlayer transmission and Talbot-like interference in the current flow on both layers. Besides, injected currents exhibit chiral features due to the twist-induced mirror-symmetry-breaking. Upon increasing the twist angle, the coupling is weakened and the monolayer electronic properties are restored. Furthermore, we predict spectroscopic signatures that allow to probe the twist-dependent interlayer coupling via scanning tunneling microscopy.