Tunable gap opening and spin polarization of two dimensional graphene/hafnene van der Waals heterostructures

Abstract

Spin polarization of graphene is the current subject of intense investigation efforts. Herewith, the interfacial electronic structure of graphene/hafnene two dimensional van der Waals heterostructures with different stacking configurations are investigated by first-principles calculations. It is found that the distinct electronic distribution and spin-polarized characteristic of the vdW heterostructures come from the intensity of orbital overlap induced by diverse stacking configurations. The Pauli-exclusion principle takes effect between the hafnene and graphene, and subsequently drive interfacial charges to transfer, which results in n-doped graphene without breaking the p-electron Dirac points. Nevertheless, the orbital hybridization motivates a π-band gap opening with metallic gap states and spin polarization in graphene. Particularly, the electronic structure, spin splitting and band gap depend on the interfacial interactions, which can be tailored by strain and electric field. Field-effect transistor based on graphene/hafnene heterostructures has been proposed. These results strongly revive this novel system as a candidate for future graphene-based electronics.