Crystalline topological Dirac semimetal phase in rutile structure ${\beta }^{\prime }$-PtO${}_2$

Abstract

Based on first-principles calculations and symmetry analysis, we propose that a transition metal rutile oxide, in particular ${\beta }^{\prime }$-PtO${}_2$, can host a three-dimensional topological Dirac semimetal phase. We find that ${\beta }^{\prime }$-PtO${}_2$ possesses a linked nodal rings structure when spin-orbit coupling is neglected. Incorporating spin-orbit coupling gaps the nodal rings, while preserving a single pair of three-dimensional Dirac points protected by a screw rotation symmetry. This Dirac point is created by a band inversion of two $d$ bands, which is a realization of a DSM phase in correlated electron systems. Moreover, a mirror plane in the momentum space carries a nontrivial mirror Chern number $n_M=-2$, which distinguishes ${\beta }^{\prime }$-PtO${}_2$ from the Dirac semimetals known so far, such as Na${}_3$Bi and Cd${}_3$As${}_2$. If we apply a perturbation that breaks the rotation symmetry and preserves the mirror symmetry, the Dirac points are gapped and the system becomes a topological crystalline insulator.

8 pages, 8 figures