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arXiv · 1809.08963

Crystalline topological Dirac semimetal phase in rutile structure $β'$-PtO$_2$

Rokyeon Kim·Bohm-Jung Yang·Choong H. Kim
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Abstract

Based on first-principles calculations and symmetry analysis, we propose that a transition metal rutile oxide, in particular $β'$-PtO$_2$, can host a three-dimensional topological Dirac semimetal phase. We find that $β'$-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 $β'$-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.

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Rokyeon Kim, Bohm-Jung Yang, Choong H. Kim. 2019-01-17. Crystalline topological Dirac semimetal phase in rutile structure $β'$-PtO$_2$. https://doi.org/10.1103/physrevb.99.045130

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