Compared to inversion-symmetric systems, the emerging bulk Dirac point (DP) in noncentrosymmetric systems is much harder and its symmetry-protection mechanism is poorly understood. In this Rapid Communication, we propose that orthogonal glide symmetries can protect two distinct types of bulk anisotropic DPs. One is the ordinary anisotropic DP that is doubly degenerate only along one invariant axis, which results from symmetry-protected accidental band crossing. The other one is a symmetry-enforced DP fixed at a non-time-reversal-invariant point, which is doubly degenerate at three orthogonal directions. This unique topological phase is exemplified by ${\mathrm{KSnSe}}_2$ in space group 108. Our work not only unveils a unique symmetry-protection mechanism but also provides a material candidate for exploring multitype Dirac fermions in noncentrosymmetric systems.

• Received 2 March 2020
• Accepted 15 June 2020

DOI:https://doi.org/10.1103/PhysRevB.102.041201