Topological phase transition in compressed van der Waals superlattice heterostructure BiTeCl/HfTe₂

Based on first-principles calculations, we investigate the electronic band structures and topological properties of heterostructure BiTeCl/HfTe₂ under c-direction strain. In the primitive structure, this material undergoes a phase transition from an insulator with a narrow indirect gap to a metal by strong spin–orbital coupling. When strain effect is considered, band inversion at time-reversal invariant point Z is responsible for the topological phase transition. These nontrivial topologies are caused by two different types of band crossings. The observable topological surface states in (110) surface also support that this material experiences topological phase transition twice. The layered heterostructure with van der Waals force provides us with a new desirable platform upon which to control topological phase transition and construct topological superconductors.