Electronic properties of van der Waals heterostructures of graphene/bismuthene and graphene/Bi₂Se₃

In recent years, the study of van der Waals heterostructures has aroused significant interest in the scientific community because of their intriguing properties and potential technological applications. On the other hand, the outstanding properties of graphene has been exploited in different fields since its discovery. Its use as building block of heterostructures looking for new physical phenomena is in progress. Using density functional theory calculations, we performed a comparative study of the energetic stability, charge densities, and electronic properties of van der Waals heterostructures formed by the stacking of graphene with monolayers of different topological character. For our study, we chose bismuthene and a monolayer of Bi₂Se₃, which are topological non-trivial and trivial insulator, respectively. Our results show significant changes in the electronic character of graphene where the Dirac cone is shifted from the Fermi level by the interaction with bismuthene or Bi₂Se₃. Particularly, this shift of the Dirac cone is due to a charge transfer that occurs in both cases but depends on each monolayer. Finally, the role of the topological character of each monolayer on the heterostructure properties is discussed.