Symmetry protected weak topological phases in a superlattice

摘要

We explore novel topological phases realized in a superlattice system basedon the Wilson-Dirac model. Our main focus is on a two-dimensional analogue ofweak topological insulator phases. We find such phases as those characterizedby gapless edge states that are protected by symmetry but sensitive to theorientation of the edge relative to the superlattice structure. We show thatmanifest and hidden reflection symmetries protect such weak topological phases,and propose bulk Z2 indices responsible for the topological protection of theedge states.