Tuning the Topological Bandgap of Bilayer‐Bi(111) Supported on Graphene

Abstract

Listen

Translate article

Based on first‐principles calculations, the electronic structures of the van der Waals heterostructures formed by bilayer‐Bi(111) and graphene are systematically studied. Although the Bi–graphene spacing is larger than 3 Å, the topological bandgap (TBG) of bilayer‐Bi(111) can be tuned by the weak Bi–graphene interaction and the stacking pattern between Bi and graphene. In the zigzag–zigzag stacking pattern, the TBG can be enlarged by reducing the Bi–graphene spacing or the buckling of bilayer‐Bi(111). Interestingly, in the zigzag–armchair stacking pattern, there is a new hybridization gap in a bilayer‐Bi(111) near Fermi level. Meanwhile, the TBG of bilayer‐Bi(111) can also be modified in the heterostructures. However, a large bandgap (more than 100 meV) can be realized in graphene by tuning the Bi–graphene spacing. The calculations suggest the importance of stacking pattern and hybridization on the electronic structures.