Abstract
Nitrogenated holey graphene (NHG) is a recently synthesized two-dimensional material. In this paper the structural and electronic properties of heterostructures of graphene and NHG are investigated using first-principles and tight-binding calculations. Due to the lattice mismatch between NHG and graphene, the formation of a moiré pattern is preferred in the graphene/NHG heterostructure, instead of a lattice-coherent structure. In moiré-patterned graphene/NHG, the band gap opening at the point is negligible, and the linear band dispersion of graphene survives. Applying an electric field modifies the coupling strength between the two atomic layers. The Fermi velocity is reduced as compared to the one of pristine graphene, and its magnitude depends on the twist angle between graphene and NHG: For is 30% of that of graphene, and it increases rapidly to a value of 80% with increasing . The heterostructure exhibits electron-hole asymmetry in , which is large for small . In NHG encapsulated between two graphene layers, a “Dirac ring” appears around the point. Its presence is robust with respect to the relative stacking of the two graphene layers. These findings can be useful for future applications of graphene/NHG heterostructures.
2 More- Received 15 July 2015
- Revised 16 September 2015
DOI:https://doi.org/10.1103/PhysRevB.92.195419
©2015 American Physical Society