Topological Weyl semimetal phases in a time reversal invariant spinless model

Abstract

We investigate the topological Weyl semimetal phases in a time reversal invariant spinless lattice model which has C4v or C2v point group symmetries. For the C4v case, the model is characterized by eight Weyl points in the kz = π plane, while for the C2v case, it is characterized by four Weyl points in the kz = π plane. For both cases, Fermi arcs can be realized on their surfaces. We find that the topological Weyl semimetal can be viewed as an intermediate phase between the topological crystalline insulator (TCI) and normal insulator, and they all can be described by the so-called bent mirror Chern numbers. What’s more, in the C2v case, the TCI phase is still present when the perturbation is small, though the Z2 invariant is not well-defined then, however, it can be well described by the bent mirror Chern number.