Larger hybridization bandgaps and topological phase transitions in the Sb-based topological insulator superlattices

With the aim of achieving a higher hybridization bandgap in the quantum spin Hall insulating heterostructures, we study topologically novel InAs/GaxIn1−xSb superlattices with inverted bandstructure. By tuning the strain and material composition of each layer in a precise manner, enhancement of the hybridization is achieved. The theoretically calculated hybridized bandgap reaches it's highest value ∼ 79 meV, which is one of the highest reported value so far. We also show that the bilayer superlattice shows a topological phase transition from the trivial insulating to the quantum spin Hall insulating to the semimetallic phase. These phases can be tuned by varying the InAs layer thickness. All the heterostructures showing large hybridization bandgaps are potential candidates for the realization of quantum spin Hall insulating states at the room temperature.