Stacking-type dependence of topological phase transitions in a superlattice of topological and normal insulators

We consider a superlattice of topological and normal insulating layers. It is known that topological phase transitions occurs with the variation of the interlayer hopping when two-dimensional quantum spin Hall insulator is hybridized with the normal insulators in the AA-type stacking. We examine how the nature of topological phase transition changes depending on the stacking type. The resulting phase diagram exhibits rich phases such as semimetal and topological ones. The properties of the edge states are also investigated in the sample of finite width. Finally we discuss the topological features of alternately stacked layers of topological and normal insulators.