Non-symmorphic symmetry-protected topological phases.

Jennifer A. Cano

Princeton University

Crystal symmetries enrich the classification of both topological insulators and topological semi-metals. However, only recently have non-symmorphic symmetries been included in this classification, which will be the focus of this talk. In particular, I will present a "topological Dirac insulator," whose surface consists of two copies of the surface of a Z2 topological insulator, protected by two perpendicular glide symmetries. Next, I will present a complete classification of symmetry-protected band crossings that can occur in spin-orbit coupled systems. These fermionic excitations consist of 3-, 6- and 8-band crossings that can be distinguished by their degeneracies along high-symmetries points and lines. This includes three-fold degenerate "spin-1 Weyl points," which display double Fermi arcs and novel magnetic oscillations.