Interfaces and superlattices of the topological insulator Bi₂Se₃

Interface states of topological materials are important for both emergent fundamental phenomena and for their potential application in future electronics and computing devices. Here, we propose different ways of manipulating the position of the energy of the surface Dirac states in the topological insulator (TI) Bi₂Se₃ relative to the bulk Fermi level, their linearity, their location, etc., by making contact with different materials. Our predictions are made by using density functional theory and model Hamiltonians. For example, in the case of an interface of a TI with a band insulator (BI) we find that the location of the interfacial topological state moves out of the topological insulator boundary to the BI side. When a TI forms an interface with a metal we find that the topological surface states can show oscillatory behavior which propagates inside the metal. We also present results for superlattices formed of a topological insulator with a band insulator.