First-principles study on the electronic structures and topological properties of Bi(110)/IV-VI and Bi(110)/V-V van der Waals heterostructures

Abstract

Based on the first-principles calculations, numerous theoretical research efforts have been made to exploit electronic structures and topological properties in Bi(110) and IV-VI groups (Sn0.5Se0.5, Sn0.5Se0.25Te0.25, Sn0.5Te0.5), V-V groups (Sb0.5As0.5, Bi0.5As0.5, α-Bi0.5Sb0.5, α2-Bi0.5Sb0.5) substrates heterostructures. Molecular dynamics confirmed that the proposed bilayer heterostructures are stable. The electronic analysis results show that the valence and conduction bands near the Fermi level are mainly contributed by Bi(110). More importantly, Bi(110)/Sn0.5Te0.5 and Bi(110)/Sn0.5Se0.25Te0.25 have non-topological properties. However, when applying 20% biaxial tensile strain, both of them have nontrivial Z2 topological invariants and topological edge states. Our findings not only breathe new power into the family of 2D materials but also highlight these 2D semiconductors as attractive materials potential for future electronics and topological devices.