STM visualization of carbon impurities in sandwich structures consisting of hexagonal boron nitride and graphene

Abstract

We study the electronic structures and scanning tunneling microscopy (STM) images of heterostructures consisting of pristine h-BN, graphene, and C-doped h-BN layers using first-principles total-energy calculations within the framework of the density functional theory. We find that substitutional doping of a C atom at B and N sites in the h-BN layer induces the different charge carrier types and asymmetric carrier densities on the graphene layer. We also find that C-atom impurity state can be clearly observed in the STM image when a C atom is doped at the N site in the h-BN layer. We discuss the relationship between the STM images and the spatial distribution of the C-induced impurity state.