Stacking-dependent electronic properties of aluminene based multilayer van der Waals heterostructures

Aluminene, one of the group III elemental monolayers, is predicted to be stable in the honeycomb configuration with metallic characteristics. In this paper, we consider aluminene-based heterostructures, investigating their stability, structural and electronic properties. The results based on density functional theory find that the interaction between aluminene and BN or graphene monolayers is weak, and is dominated by the van der Waals forces. The electronic structures calculated using the HSE06 functional show aluminene/graphene and aluminene/BN bilayers to be metallic. Likewise, graphene/aluminene/graphene trilayers are predicted to be metallic. However, BN/aluminene/BN trilayers are predicted to be semiconducting in nature with finite gaps. The results suggest that the interaction of Al atoms with N atoms facilitates the opening up of the gap in trilayer heterostructures, unlike the graphene/BN heterostructures, where inequivalence of the carbon lattice leads to the bandgap. The stacking-dependence of the electronic structure is affirmed by the electron tunneling characteristics calculated for the trilayer heterostructures. The predicted relationship between topology and electronic structure can, therefore, be exploited to tailor the electronic properties of aluminene-based heterostructures.