Mirror-protected delicate topological phases in three dimensions

In this talk, we explore two novel types of delicate topological phases in three dimensions that are protected by mirror symmetries. In particular, the quantized Weyl dipolar semimetal is a new class of Weyl semimetals, whose Fermi arc surface states arise from delicate topology rather than the conventional Chern physics. Any two Weyl nodes in this phase, if related by the mirror symmetry, form a quantized Weyl dipole. In addition, we also construct and investigate a mirror-indexed delicate topological insulator with a classification. Our work paves the way for understanding mirror-protected delicate topological phenomena in three dimensional crystals.